1 Raman spectroscopy
Raman spectroscopy is a scattering spectroscopy discovered by Indian physicist CV Raman in 1928. Raman spectroscopy, as a means of analysis and testing of material structure, was first widely used in scientific research. With the advancement of technology and the deepening of the theory, Raman spectroscopy has been widely used in materials, chemicals, petroleum, polymers, biology, environmental protection, geology, etc., and gradually entered people's lives. The application of Raman spectroscopy in the identification and research of archaeological materials has been very active in recent years. This is a combination of social science and natural science, and its meaning is self-evident. This paper reviews in detail the many applications of this technology in archaeological research.
Raman spectroscopy is not esoteric. It often relies on the vibrational spectrum of crystals or molecules to distinguish crystals or molecules. This is like Li Guyi and Guan Mucun singing. As long as they sing two sentences, we can distinguish who sings because the spectrum of sound determined by their vocal resonances is different. The sound spectrum is the vibration spectrum. Everyone has their own sound spectrum. Each molecular crystal also has its own sound spectrum, but in general we can't hear it. At present, we use laser to excite the vibrational spectra of these molecular crystals and record them to distinguish different molecules.
Raman spectroscopy has its unique advantages as a means of testing at the molecular level. The measurement of micro-Raman spectroscopy with photons as a probe is a non-destructive, non-contact measurement, which is extremely important for the application of cultural relics law. Secondly, the obtained vibration spectrum information of the sample is easy to identify, so it is called Fingerprint spectrum, the identification and identification identified by this is very reliable and accurate. Third, micro-analysis can be performed using modern micro-Raman, and the profile analysis obtains information on a small amount of wrap, such as whether the mineral product is artificially filled or falsified. Fourth, compared with X-ray fluorescence and electron microscopy XPS, the information obtained is information at the molecular level, not information of a single atom.
However, Raman technology has its own drawbacks such as low detection sensitivity; it is not easy to do quantitative analysis; it is not suitable for analysis of metal alloys or fingerprint analysis of elements; it is impossible to analyze fluorescent substances or substances containing fluorophores. At this time, some special techniques such as surface enhanced Raman, resonant Raman, etc. are needed to overcome the shortcomings.
2 Comparison of Raman spectroscopy with other analytical methods in archaeology
Despite some shortcomings, Raman technology has several outstanding advantages compared to other analytical tools commonly used in archaeological laboratories to identify molecular solids. It is worth noting that the complexity of archaeological materials often requires the use of multiple analytical tools. To do a complete analysis.
2.1
3.1 ancient pigments
The analysis and study of ancient painted pigments is an important part of scientific archaeology and cultural relic protection. It can provide valuable information for exploring the development of ancient pigment technology and research related protection schemes. In addition, the study of the structure and composition of ancient painted pigments has become a measurement. The age of cultural relics, the origin of raw materials and the important basis for the protection and restoration of related cultural relics. In the authenticity identification of ancient artifacts, this part of the work is also very critical, and the pigments in some counterfeits are likely to be modern synthetic.
3.1.1 Rock Art and Grave Painting
The paintings in the cave ruins and grottoes may be the earliest records of historical paintings of prehistoric people. The technical analysis of these paintings is to understand mineral pigments and prehistoric binders, to distinguish between artificial and natural decorative patterns, or modern graffiti, in different locations and different art types (religious, ceremonial , historical) mid-age changes, artistic geology, biological, man-made destruction.
Using the molecular properties of Raman microscopy, the researchers identified pigment samples as "disordered goethite", calcite, quartz and rutile. Pigment samples from three prehistoric caves in the Kelsey region of France contain red iron. The importance of sampling minerals, carbon black, manganese oxides/hydroxides, and the environment from the time was to identify that calcite, quartz, and rutile were determined by the geological presence in the cave, avoiding incorrect human interference.
Prehistoric stone murals in numerous cavern sites in the southwestern United States use FT Raman microspectroscopy to determine the nature of the layer confirming the presence of calcium oxalate hydrate (CaC2O4·H2O), which is due to the biological activity of moss on murals and Church Building Damage The red and black pigments used in stone murals were identified as red vermiculite (Fe2O3+clays) and unspecified MnO2 minerals [5]. The identification of MnO2 minerals was first determined by the published MnO2 vibrational spectra. The identification of MnO2 in stone murals is based on a single band at 620 cm-1.
Raman spectroscopy is also used to study top bone art in some prehistoric grotto sites. For example, in the large curved area of ​​Texas, the black pigment contains MnO2 in the oil painting of the large curved area, and the pyrolusite structure hematite is proved by XRD. Calcium oxalate is present at the same time due to the natural fading caused by the leaching of the surrounding stones by hyphae and moss. The Argentine ruins are determined by white paintings on black-deformed rocks. The Raman spectroscopy shows that the white pigment on black rocks is a thin lime powder (Ca(OH)2) made of white gypsum and calcite.
The pigments of the decorative top bone art in the historical period are much richer than in the prehistoric period. The study of the funerary art in the Roman tombs of Crimea identified many interesting pigments such as lead dan and Egyptian blue CaCuSi4O10, carbon black. The identification of lead dan may be the first report of this coloring agent used in the 1st century AD. The light blue pigment found in the tomb of Hebei Province in the 6th century AD. The tomb is considered to be the tomb of the Emperor Gaoxuan Emperor of the Eastern Wei and Northern Qi Dynasty. It was identified by Raman spectroscopy as a calcite - a very common mineral pigment Camagna et al. The preparation process of Egyptian blue and Egyptian green pigments was studied by Raman microspectroscopy. Their elemental composition or morphology is used to characterize the identification of molecules or crystal structures. Black copper ore (CuO) was identified, confirming that the synthesis of the two compounds was carried out in an oxidizing atmosphere. The silica portion is all-quartz; in the green pigment, α-cristobalite is observed. In addition, a blue crystalline compound of the attapulgite (CaCuSi4O10), Egyptian blue was obtained.
3.1.2 Painted pottery pigment
The composition analysis of the pigments of a large number of painted pottery helps us to understand the information about the painting process and the raw materials used for painting, which is of great significance for the effective protection and restoration of painting.
Raman microspectroscopy used to analyze the red oil-coated ceramics of southern Italy based on the red pigment used in the ornamentation. The medieval Ramina–manganese–red (RMR) style ceramics were analyzed by Raman spectroscopy and XRD. The agent was identified as an Fe(III) oxide. However, the RMR fragments collected from the three sites were analyzed by XPS, SEM, Raman microspectroscopy, and the results showed that different production centers could be identified due to the different red pigments or pigment mixtures used. Pure hematite, pure lead yellow, or a mixture of hematite and lead yellow is consistent with ceramics at three production sites. In addition, the process is different in these relevant locations close to Italy, and these results indicate that the analysis of the pigment can provide evidence for the origin of the RMR ceramics without context.
Similar work was done on fragments of blue and black glaze (lower quality medieval ceramics from the same area), with a blue background provided by lapis lazuli (lapis lazuli, Na8[Al6Si6O24]Sn-) instead of the imaginary cobalt base The use of celestite in ceramics produced in the mid-13th century is the first high-priced mineral found in ceramic glazes. The advent of lapis lazuli is the first use of minerals in Italian art as a pigment.
Persian ceramics as a pigment in the 13th century Iranian large-mouth can also be identified by Raman microscopic identification of celestite in metallurgical technology, providing an upper limit of 1500 ° C for the baking temperature of the glaze ( 1000 ° C is the decomposition temperature of lapis lazuli).
Zhang Pengxiang et al. confirmed that the blue-green glaze on the ceramic surface is mainly blue-lined stone Al7(BO3)(SiO4)4O7 and the yellow glaze is mainly a yellow variant of Aluminium Telenate, black. The glaze is mainly amorphous carbon, and the red glaze has a strong fluorescence. The 5000-year lead-free glazed pottery found in Henan, China, was analyzed by Raman microspectroscopy. The vanadium (including Al2O3·2H2O) was a white ornament, and the magnetite (Fe3O4) was used as the black part. When the particle size is reduced, the characteristic wave number of the magnetite in the reference sample is red-shifted, widened, and the strength is lowered. Among these fragments, magnetite particles can be estimated from their Raman spectra, with particle sizes ranging from 20 to 60 nm, and XRD and TEM can also be used to estimate particle size. Particle size changes in this range affect the subtle changes in pottery color, and nanopreparation techniques may have been mastered by ancient artists.
The Raman spectroscopy study of white-colored painted pottery from the Yangshao Cultural Relics in Xishan, Henan, China, found that the use of anatase anatase as an ancient pigment has not been recorded before. The appearance of this pigment indicates that the sintering temperature is low because of anatase The ore is easily converted into a rutile structure between 800 ° C and 1000 ° C.
FT Raman analysis of the blue pigment particles of the Bottesford corrugated glaze in England, and found that the colorant is azurite (2CuCO3·Cu(OH)2) (band at 406 cm-1) azurite as a pigment The low temperature sintering technique was confirmed because the carbonate mineral decomposed into black black copper ore (CuO) at -300 °C.
The pigments of painted pottery figurines unearthed from Yangling in the Han Dynasty were analyzed by Raman spectroscopy. It was found that the purple pigment contained BaCuSi2O6, which was first synthesized by the ancients in 1845 before the different pottery materials of different regions and different ages. It can be used to trace ceramics. Information on the age of origin. However, the current low-temperature painted pottery is often composed of a small amount of color components in the main component. In this case, the analysis of a small amount of ingredients is still insufficient. Therefore, the information provided is not accurate, and the establishment, enrichment and improvement of the database is very urgent.
3.1.3 Manuscripts, paintings
The ancient artists collated with the manuscripts and decorative manuscripts of the pigments to identify the binders, inorganic pigments, and organic dyes. Western experts studied the Paris Bible (about 1275), Latin North Italian Roulette Hymns (13th Century) Germany The sacred set of the flower of Denmark is decorated with the Icelandic law book Skard copyca (1360). Lead-free pigments were found in Icelandic law books, probably due to the lack of lead ore in Iceland and the use of ash-white and vermilion/red meteorites. Lead-containing pigments are white lead or red lead. Oriental manuscripts include the Persian manuscript - "Anatomy of the Body" (19th century), the 16th century "Petace in Praise" early manuscript copy Qazwini manuscript "Wonders of Creation and Oddities of Existence", the late 13th century Arab encyclopedia Work, 16th century Indian-style manuscripts of the Koran, Iran or Central Asia, 13th century, Eastern Arab handwriting Byzantine/Syrian New Testament, Iraq, 13th century northern China Dunhuang manuscripts and textile fragments Thailand, Java, North Korea, China and other manuscripts.
3.1.4 Ancient techniques and pigment synthesis studies
The characterization of Raman spectroscopy is applicable to the understanding of ancient techniques and techniques, and to understanding the techniques produced by the color of art. Resonance Raman spectroscopy can be used to study the effects of final color synthesis conditions and the properties of historical pink enamel pigments. In the famous chromium-doped tin silicate used in the French Sevres Factory, it is found that the calcination temperature affects the presence of the second phase (pigment crystallization), and the effect of particle size on the color of the pigment is very important for the ancient preparation process of Egyptian blue and green pigments. Mann microspectroscopy was studied. From the New King period (1567–1085 BC), the crystalline inclusions in the blue and green pigments of Egypt were used as chemical tracers in the preparation process. Raman spectroscopy showed that the blue pigment consisted of attapulgite (CaCuSi4O10), while the cyan pigment was composed of Composition of β-calcium silica.
In addition, the Egyptian blue scorpion analog, namely Han Cu (BaCuSi2O6), has a unique Raman spectroscopy and uses Raman spectroscopy to identify painted pottery figurines in Chinese graves dating back to 1900 [25].
In the Egyptian blue and Egyptian green samples, in addition to high temperature - cristobalite, amorphous quartz was identified. - Cristobalite is rarely present in Egyptian green, indicating that the green pigment is produced at a lower temperature. Further studies of the two pigments identified CuO and SnO2 particles, indicating that all used were oxidizers rather than reduction furnaces, bronzes, and Cu-Sn alloys, which were the raw material sources for these pigments.
3.2 ceramics, glass
3.2.1 Ceramics
Ceramics is one of the most important life in human history, one of the production materials. Many archaeological encounters have the identification of ancient ceramics and the analysis of the mineral composition and composition of ancient ceramic carcass and glazed surfaces, for the identification of the origin and age of ancient ceramics. It is of great significance to study the sintering process technology and development process of ancient ceramics.
The Longquan-type Chinese blue-and-white porcelain piece was considered as a product of the Southern Song Dynasty (1127-1279) period. It was excavated in 1934 in Mapungubwe, South Africa (the Iron Age site of the 13th century Limpopo Valley). The Raman polymerization index Ip calculated from the glazed spectrum of the ceramic sheet indicates that the porcelain sheet needs to have a higher sintering temperature than the calcium-rich Southern Song Longquan glaze, and Prinsloo attributed the tile to the Yuan Dynasty (1279–1368 AD) or Early Ming Dynasty (1368–1644 AD)
Zhang Pengxiang and other researchers used microscopic Raman spectroscopy to test and analyze micron-sized grains in paleo-ceramic ceramics and glazed surfaces, and studied the mineral composition of ancient ceramics [[[49] Li Zhidong, Zhang Pengxiang, Palestinian ancient ceramics Microscopic Raman Spectroscopy Analysis [J]. Chinese Journal of Light Scattering, 2000, 12(2): 97-100.]]. They measured two pieces of ancient ceramic fragments and analyzed the main mineral components that make up the ceramic fragments. Sample 1# contains minerals such as quartz, aragonite, and anatase. Sample 2# contains minerals such as quartz, slate, anatase, anthracite, calcite, and borofluorite. In addition, laser Raman molecular microprobe technology was used to study the molecular network structure of Yaozhou kiln celadon and black enamel glass phase, and combined with the glaze microstructure observation results, the differences in firing temperature between celadon and black porcelain were discussed [[ [50] Yang Zhongtang, Li Yueqin, Wang Zhihai, Xu Peicang, Research on molecular network structure characteristics of ancient Yaozhou celadon and black enamel glass phase [J]. Northwest Geology, 1996, 17(2): 49-55.]].
Enamel glaze is an important structural layer on the surface of ceramic products with glass phase as the main body. It is an important factor affecting the appearance quality of porcelain products, especially art porcelain. Therefore, it is especially important to study the glaze glass phase structure. Similar to silicate glass, the addition of glaze network modifier destroys the Si-O linkage and modifies the degree of polymerization, thus modifying the relative strength of the Si-O bending and stretching modes. The ratio is related to the glass structure and the temperature of the kiln. It analyzes the different production techniques of porcelain, painted pottery, pottery and glass representing Asia, Islam and Europe.
3.2.2 Glass
Because the Raman scattering of vitreous silica is weak, and the fluorescence is strong due to the burial environment or product processing, the glass products are not studied in the early stage using Raman spectroscopy. However, the investigation and analysis of the art glass from the 18th to the 20th century transformed the fluorescence of the annoying glass product into the ratio of the intensity of the Raman band of the glass silica at 1080 cm-1 to the intensity of the fluorescent band at 2000 cm-1. The analytical variable is related to the age of the glass. Products with a life span of more than 200 years were tested and the calibration curve was very sensitive and linear. This program is only used to test relatively young, clear and similarly composed glass and it is well preserved.
In order to discover the technology in the production process, ancient Phoenician beads, tessarae, and jewelry composed of clear and colored glass were studied, and lead-containing glass was identified from soda lime glass according to the characteristic shape of the silicate Raman belt. Sapphire (SnO2) was found to be used as a diluent or opacifier, and pigments, mineral inclusions, and imitation materials were also identified. These results were further confirmed by SEM-EDX and XRF. Hematite is used as a deep reddish-brown pigment in the stained medieval and Victorian British church glazing.
3.3 stone artifacts
Raman microspectroscopy provides a compelling, non-destructive test. Raman spectroscopy is another option for cross-sectional rock description, XRD, and SEM analysis when the surface of the article is the region of interest or can represent the entire article. Raman spectroscopy is very useful in geological archaeology and mineral product analysis. 3.3.1 Mineral Art
Smith et al. summarized the advantages of Raman spectroscopy in the analysis of several mineral products, including the Celtic Glass Fortress and the Olmec “Green Jade†Axe. The classification of mineral samples from museum collections.
Two axes composed of green jade were identified by Raman microspectroscopy [56], consisting of lanthanum (CaTiOSiO4), amphibole-containing eclogite material, and jadeite-jasper (NaAlSi2O6). One of the axes is the product of the former Columbus archaeological site on Cozumel Island in Cozumel. Cozumel Island lacks an eclogite facies, the first recorded eclogite of the pre-Columbian period in the Americas. Smith and Gendron believe that the possible source of the material of the product is the nearby area, emphasizing the use of Raman spectroscopy to find the source of the product without damage.
A Raman analysis of mineral inclusions of more than 350 garnets from French jewellery from the 5th to 7th centuries of the Merovingian period, mentioning another technique of origin research. Particle-induced X-ray emission ( PIXE) The main elemental composition of the garnet determined by the spectrum can be classified into an iron-aluminum garnet FeII3AlIII2(SiO4)3), a magnesite (MgII3AlIII2(SiO4)3) or an intermediate of the two. The elemental analysis by PIXE is compared with the data in the literature, and the source of garnet is Eastern Europe and Asia.
Many French museum collections of minerals have been successfully studied using portable Raman instruments with remotely controlled laser fiber optic probes. The structure and related pigments of several large carved stone statues in Paris were carried out using a Raman system with a horizontal moving microscope. Identification. The spectrum of the Aztec skull engraved by a single transparent mineral crystal corresponds to quartz, confirming that the historical role of the material is "rock crystals".
Domestic research on stony minerals has also been carried out. For example, Raman spectroscopy has been used to systematically measure the stone axe unearthed in Tengchong, Yunnan. Some people have judged that this stone axe is made of jade, which caused The introduction of jade to China or Yunnan Tengchong also has the controversy of jadeite source. The measurement of micro-Raman has undoubtedly proved that the stone axe unearthed from Tengchong is a kyanite mineral rather than jadeite, confirming that Professor Yang Boda’s suspicion is correct [[[ 60] Zu Endong, Raman Spectral Analysis of Ancient Relics[J].Journal of Kunming University of Science and Technology(ç†ç†å·¥å¦æŠ¥), 2004, 29(3): 26-28.]].
3.3.2 Identification of gemstones
Raman spectroscopy is widely used in gemology to identify fake, imitation, artificially jeweled jewels. The analysis of two jewel-like church pieces from the Basel Cathedral, the Holy Cross and the Dorothy sacred body A large number of colored glass "stones" and pairs of two connected quartz crystals have colored crack layers. The paired stones in Dorothy's sacred body are colorless, indicating that the adhesive layer uses a variable coating. Twelve gems inlaid on the cover of the Tours Gospel, a delicately decorated leather manuscript stored in the British Library, were identified by Raman spectroscopy as silica, amethyst, emerald, iron garnet and sapphire.
After the Middle Ages (around the 1920s), the Holy Cross (called Heinrich Cross) was studied using a movable Raman microscope. The Heinrich Cross is now preserved at the Museum of Practical Art in Berlin, including 68 gems inlaid on both sides of the cross. These gemstones were analyzed directly in the museum using a microscopic fiber Raman analyzer to identify quartz, corundum, garnet, ruby, etc.
For the identification of gemstones, researchers in China have also used Raman spectroscopy to analyze the composition of gemstones. He Mouchun et al [[ [65] He Mouchun, Zhu Xuanmin, Hong Bin, Raman Spectral Characteristics of Inclusions in Yuanjiang Ruby in Yunnan[J]. Journal of Gem and Gemology, 2001, 3(4) : 25-27.] Laser Raman spectroscopy studies on inclusions in the Yuanjiang ruby ​​in Yunnan show that the ruby ​​contains crystalline mineral inclusions such as zircon, calcite, apatite and rutile. The results of Schrader et al. using Raman spectroscopy to study diamonds show that natural diamonds show strong Raman peaks at 1332 cm-1, which makes the identification of true and false diamonds very simple. Diamonds have different inclusions. For natural diamonds that contain fluorescence when the sample is measured, N IR-FT-Raman is used to avoid fluorescence interference. Raman and IR spectra of the diamonds are systematically collected for identification. Liu Shewen et al [[ [68] Liu Shewen, Guo Maotian, Liang Erjun, Shen Shubo, Application of Laser Raman Spectroscopy in Jade Identification[J]. Chinese Journal of Light Scattering, 1999, 11(5) : 194-197.] The Raman spectroscopy system measures nephrite (skin jade, green white jade, sapphire, jade), Jingbai jade, white marble, jade, Dushan jade, jade jade, green Henan jade, bloodstone, balin stone, lapis lazuli, glass, etc. Spectra; Aponick et al. compared the Raman spectra of glass, zircon and other gemstones for the authenticity of gemstones.
Zu Endong et al. used microscopic confocal Raman spectroscopy to identify natural jade and jadeite A and B goods [[ [70] Zu Endong, Duan Yunqi, Zhang Pengxiang, application of microscopic confocal Raman spectroscopy in gem identification] J]. Journal of Yunnan University (Natural Science Edition), 2004, 26(1): 51-55.]], natural jade has no bands in the high band, and non-natural jade has bands in the high wavenumber. As long as there are 1116, 1609, 3069 and 1189 cm-1 in the Raman spectrum of the jade jewelry, the bands unique to the epoxy resin are different from the wax, especially the first two bands, the sample can be determined as jadeite. B goods.
3.4 metal objects
The Raman technique of photon probes is difficult to study in most pure metals and alloys because it is difficult to penetrate into the metal, but it is suitable for identifying surface corrosion of metal products and research on such as copper-green layers. . In addition, due to the mixing of other components in metal smelting, such as slag, many useful information can be obtained by analyzing the inclusions.
The analysis of Chinese bronze-cash tree is the use of this technique. The identification of the Raman microspectroscopy of the corrosive components on the branches of the cash cow indicates that the entire cash cow is actually composed of five independent cash cows, each of which is exposed to different Under the environmental conditions, there are therefore different degradation products. Examination of the transverse interface exposed to the surface detected sulfate and sulfide corrosion products, indicating that the cash cow was exposed to modern air pollution or buried in anaerobic soil in the presence of sulfate-reducing bacteria. The alternating corrosion layer implies a cyclical change in the burial environment of the cashmere branches. For further identification of some modern pigments, Phthalocyanine Blue (CuC32H16N8) can be used as a part of the cash cow to pretend to be a realistic patina layer.
Light blue corrosion materials on numerous copper alloy articles can be identified by Raman spectroscopy and other techniques. Studies have shown that in some cases the light blue corrosive material is a product of the display environment rather than the natural patina. The composition of the coins is classified and the previous burial environment is known from the analysis of the corrosion products.
Wang Yilin et al. studied the copper corrosion of the Yuan Dynasty unearthed in Yunnan Lufeng, determined the composition of the copper mirror body and its surface corrosion products, and analyzed the anti-corrosion technology adopted by the bronze mirror in the Yuan Dynasty. The main components of the copper mirror surface corrosion products are CuCO3·Cu(OH) 2 and Cu 2 O. There is a layer of iron-aluminum alloy on the surface of the copper mirror, which has good anti-corrosion effect [[74] Wang Yilin, Yang Qun, Zhang Pengxiang, Li Chaozhen, Raman spectroscopy study of copper mirror corrosion in Yuan Dynasty [J]. Spectroscopy and spectral analysis, 2002, 22(1): 48-50.]]. How this surface alloy is plated is still an unsolved mystery.
Yang Qun and others used Raman combined with XPS to study the bronzes in the late Spring and Autumn Period and the early Warring States Period in China. The non-destructive study on the ancient bronze spears and the bronze mirrors unearthed from Wanjiaba in Chuxiong, Yunnan, and the main corrosion products on the surface of bronze spears. There is CuCO3·Cu (OH) 2 . The main components of the black hard material on the surface of the bronze spear are Cu2O and SnO2, and the spear tip has good corrosion resistance [[75] Yang Qun, Wang Yilin, Zhang Pengxiang, Li Chaozhen, Raman spectroscopy for the corrosion of ancient bronze spears Research [J]. Journal of Light Scattering, 2001, 13(1): 49-53.], [[76] Yang Qun, Wang Yilin, Zhang Pengxiang, Li Chaozhen, Yunnan Bronze Anti-corrosion Micro-Raman Spectroscopy and EPMA Study [J]. Journal of Light Scattering, 2005, 17(2): 192-199.]].
In addition, in addition to copper products, the corrosion products of archaeological iron products were identified. The most frequent forms of corrosion of iron archaeological works were mainly formed by goethite wrapped in magnetite. This form was identified from a sample of four different soil sites. Because the soil solution dissolves into the iron component for dissolution or precipitation
3.5 Textiles and plant fibers
The Raman analysis of resins and dyes used in combination with dyed mordants has attracted great interest from archaeologists. Many dyed chromophores have a resonant Raman effect, so there are very few concentrations of these colors in the cloth. The agent can still be detected. Less attention has been paid to the identification and study of plant fibers used in the manufacture of traditional and modern social textiles, baskets and mats. However, the Raman spectroscopy of various natural fibers was classified in detail. The study of real archaeological materials, including flax, jute, ramie, cotton, kapok, sisal, and coconut shell fibers, was proposed to identify ancient textiles and Household goods and methods of determining the state of preservation of the fibers. Cellulose ubiquitous in the above fibers includes glucose monomers linked by ether linkages (C-O-C). Since the ether bond (C–O–C) junction tends to be enzymatically and oxidatively decomposed, the condition of the ancient fiber can be estimated from the ratio of the ether bond (C–O–C) to the CH2 Raman band.
A preliminary study of archaeological textiles was carried out by Fourier transform Raman spectroscopy. The selected samples were flax samples from two locations, one was the mummy package buried in the Seventh Dynasty stone tomb in Egypt (about 1900 BC), and the other was AD. The cloth in the collective tomb near the Dead Sea in 614. Compared with pure cotton (another cellulose-based natural fiber), there is a clear difference between the two [79].
3.6 Biological materials (skin, hair, teeth, bones, ivory)
There are a large number of Raman analyses of human and animal biologics, including teeth. Due to the fluorescence of these materials themselves, the analysis of these articles was performed using NIR lasers and FT Raman. These types of archaeological items are diverse, including detecting the preservation status of biological materials, determining the cause of death in living organisms, treating dead bodies after death, analyzing the body art of disease or skin damage after death, and determining the animal species of biological materials. In the case of changes in the artifact's composition to specify the time lapse since death. To determine age, the FT Raman luminometer was used to detect the ratio of organic (collagen) and inorganic (apatite) content in modern and ancient teeth. The protein loss in the tannin is related to the age of the biological product, and the calibration curve given is the ratio of the age of the product and the ratio of CH2 stretching vibration to phosphate strength. The relative loss of protein was faster in the first 1000 years of burial and was more sensitive to this period. This age-determining method is useful over other scientifically tested age techniques, such as isotope carbon determinations, which are useless for relatively young biological products.
Dry or mummified corpses can be carried out intent, such as the famous Egyptian mummies, caused by a very dry burial environment. The reason for the mummification of some archaeological residues cannot be determined solely by inspection. To detect natural or artificial mummification chemical tracers, Edwards used a near-infrared Fourier transform (NIR-FT) Raman spectroscopy to compare the skin samples of ancient burial mummification, such as the Arctic glacial mummies (5200 BP). [94], Mully, the extremely cold plain of Greenland [93], and the mummies (1000 BP) in the arid desert of Peru [91, 92]. By controlling the relative intensities of keratin (protein) and fat (fat) Raman bands, the cause of mummification and the state of preservation of the body can be estimated. All mummies suffer from the digenesis of some skin tissue, although the outer skin is well preserved. The amino band attributed to skin keratin is broadened compared to modern skin samples, indicating that the secondary structure of the protein changes as the drying and aging processes change. The change or degradation of protein structure was found in the Greenland mummies 500 years ago and the Peruvian mummies 1000 years ago, with the same broadening of the Iceman spectrum of 5200, indicating that most of the changes in skin molecular structure occur in natural mummification. The process is relatively short in time. The increase in oil content in the lightly pigmented Peruvian mummified skin sample indicates that external components such as ointments or balms may be applied to the Peruvian mummies prior to burial.
In addition, the identification of anhydrous thenardite or salt cake (Na2SO4) (ancient preservative material) by FT Raman microscopy confirmed that the mummification was at least partially artificially achieved. Evidence for preservatives is given by spectral information on the well-preserved alpha-helix and beta-cleavage protein secondary structures in the skin [93].
Ivory is a common material used to modify objects throughout history. The animal source of Ivory (ivory) reveals important information about the use of ancient biological resources, trade patterns, and processes. However, since ivory often forms fancy crafts, many typical physical tests, such as Shreger line patterns, are not feasible to identify source types. Quickly distinguishing different ivory components is based on their Raman spectra, identifying alternatives used in ancient and modern imitations [98, 99, 101, 103]. There are subtle changes in the Raman spectra of different elephants and hairs, mainly in the relative band strength of 1000-1100 cm-1. The ivory spectrum is attributed to Asian elephants, African elephants, mammoths, narwhals, juveniles, hippos, whales, and walruses. At present, the number of sample components analyzed is too small to be identified based on the difference in these ivory spectra.
FT Raman spectroscopy was used as a non-destructive analysis tool to assess the degradation state of hair samples for archaeological and research purposes. This work successfully used FT Raman spectroscopy to study the skin of modern hair and ancient keratinous bio-polymers such as mummies. Fourteen hair samples from 13 different depositional environments were analyzed. Changes in the amide I and amide III modes near 1651 and 1128 cm-1 provide a change in degradation, and the degradation of the hair is expressed by varying or decreasing the intensity of the band (generally wider band) and the drift of the characteristic vibration band. [95].
4 Conclusion
The advancement of Raman spectroscopy has laid the foundation for its entry into the field of archaeological and cultural relics identification. In the identification of archaeological ceramics, Raman can form useful information from the mineral composition of the ceramic body, the characteristics of the origin and the composition of the glaze to obtain the origin of the ancient ceramics and the production process at that time. In addition to understanding the important information at that time, the study of ancient dyes also provided an important basis for the identification of the authenticity, protection and repair of cultural relics. In the identification of gemstones, micro-Raman is particularly important. In addition to the identification of true and false fingerprints, the filling of different types of gemstones in tiny areas can not escape the microscopic measurement. From the measurement of the package, you can know the origin of Baoyu, or whether it is artificially manufactured. A Raman study of ancient human mummies shows that measurements from the skin and teeth can provide information on the time of death and whether it is an artificial preservative mummies. The biggest advantage of Raman spectroscopy is the measurement of contactless and non-damage, which is the most important in the identification of cultural relics and archaeological research. The amount is rarely used. The detailed and non-destructive identification of a small amount of material provides archaeologists with invaluable information about the product, helping people understand the state of the art, cultural and trade exchanges, socioeconomic status and other information. This is indeed an important contribution of the natural sciences to the development of social sciences. With the understanding of the application of Raman spectroscopy in archaeology, Raman spectroscopy will play an important role in the study of precious cultural relics around the world.
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· Handwoven premium resin wicker UV resistant
· Rust-resistant powder-coated frames
· Different size and design for your selection
· Accept OEM, ODE design, factory price
We have different design rattan flower pot, different size for your selection, you can decorate your home or garden, make your life clean and neat.
If you have any questions, please contact with us directly. Rattan Flower Pot are produced by Golden Eagle Outdoor Furniture With High Quality and Good Appearance. Welcome you can visit our Factory.For any inquiry,Please send mail directly to us.
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Golden Eagle Outdoor Furniture Co., LTD. , https://www.geleisurefurnitures.com