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Organic matter in lake sediments contains information that can be used to reconstruct lake environmental histories over decades or centuries. In this study, we used organic geochemical proxies (i.e., total organic carbon [TOC], TOC/total nitrogen [TN] atomic ratios [C/N], stable carbon isotope ratios of TOC [δ13CTOC] and palmitic acid [δ13CC16:0], and nitrogen isotope ratios of bulk sediment [δ15Nbulk]) in sediments from Lake Kawaguchi, Japan, to reconstruct detailed histories of the organic matter accumulation and lake productivity over the past 130 years. Vertical profiles of the mass accumulation rate (MAR) of TOC in the eastern lake basin (core KAW14-7A) showed parallel increases with the C/N ratio from the 1960s to the 1980s, indicating an accelerated delivery of terrestrial organic matter via anthropogenic land-use change. In contrast, the C/N ratios in the western and central basins (cores KAW14-1A and KAW14-4B, respectively) were almost constant prior to the 1980s, suggesting that the increasing trends in the TOC MAR values in these cores are most likely attributable to the onset of eutrophication associated with rapid economic growth after the mid-1950s. On the other hand, the δ15Nbulk showed a gradual increase from the late 1870s, providing evidence for anthropogenic nitrogen input to the lake prior to the apparent eutrophication. After the 1960s–1970s, the δ15Nbulk values rapidly increased, demonstrating water deterioration associated with the direct nutrient discharge into the lake from domestic wastewater. The δ13CC16:0 profiles displayed similar increasing trends to δ15Nbulk from the mid-1960s, demonstrating a close relationship between lake productivity and anthropogenic nitrogen input in Lake Kawaguchi. Our geochemical records as a whole clearly show high algal productivity and enhanced deposition of organic matter in recent decades, suggesting that the amelioration of the lake water is a likely consequence of the transfer of nutrients to the sediment by enhanced productivity, rather than a decrease in the amount of nutrient inflow into the lake.

Multidisciplinary research was carried out at the new Late Pleistocene Bokhan site in the Baikal region (Fore-Baikal) including geochemical and petrochemical X-ray fractions, palynological and palaeozoological studies, and AMS-dating. Four palynological complexes show a development of vegetation from open meadow-steppe landscapes that are replaced by meadow steppe with small areas of tundra vegetation to pine and pine-birch boreal forests. The fauna included molluscs, reptile and mammals of tundra, steppe and taiga inhabitants. It is a so-called no-analogue fauna extant analogy of species composition which reflects tundra-steppe landscapes in conditions of cold and dry climate during Sartanian time (MIS 2) (layers 1–2) and tundra-forest-steppe landscapes with more comfortable climatic conditions, during the end of The Pleistocene (layer 3).

Summary The Palaeognathae comprise the flightless ratites and the volant tinamous, and together with the Neognathae constitute the extant members of class Aves. It is commonly believed that Palaeognathae originated in Gondwana since most of the living species are found in the Southern Hemisphere [1–3]. However, this hypothesis has been questioned because the fossil paleognaths are mostly from the Northern Hemisphere in their earliest time (Paleocene) and possessed many putative ancestral characters [4]. Uncertainties regarding the origin and evolution of Palaeognathae stem from the difficulty in estimating their divergence times [1, 2] and their remarkable morphological convergence. Here, we recovered nuclear genome fragments from extinct elephant birds, which enabled us to reconstruct a reliable phylogenomic time tree for the Palaeognathae. Based on the tree, we identified homoplasies in morphological traits of paleognaths and reconstructed their morphology-based phylogeny including fossil species without molecular data. In contrast to the prevailing theories, the fossil paleognaths from the Northern Hemisphere were placed as the basal lineages. Combined with our stable divergence time estimates that enabled a valid argument regarding the correlation with geological events, we propose a new evolutionary scenario that contradicts the traditional view. The ancestral Palaeognathae were volant, as estimated from their molecular evolutionary rates, and originated during the Late Cretaceous in the Northern Hemisphere. They migrated to the Southern Hemisphere and speciated explosively around the Cretaceous-Paleogene boundary. They then extended their distribution to the Gondwana-derived landmasses, such as New Zealand and Madagascar, by overseas dispersal. Gigantism subsequently occurred independently on each landmass.

This article investigates the marine reservoir effects from apparent age differences among molluskan shells, birds, and sea mammals from the Hamanaka 2 archaeological site, Rebun Island, Japan, which was occupied during the latter half of the Late Jomon period (1300−1200 cal BC). The radiocarbon ages were younger in the order of charred wood14C yr. ΔR values of bone collagen for Alcidae (a family of seabirds) and Japanese sea lion were 289 and 389 14C yr, respectively. A ΔR value of 447±55 14C yr was obtained on charred material from the inner surfaces of potsherds at Hamanaka 2. The different reservoir effects relate to the differences in the diets or habitats of the shellfish, sea lion, and seabird remains at the site.

Integrated studies of the geological context and fauna of Palaeolithic sites made it possible to reconstruct climate and environments of Baikal Siberia during MIS 3 - MIS 2. The main constituents of the faunal assemblages are small mammals which are a reliable bioindicator of landscapes and climates of the past. In the Fore-Baikal area, fauna recovered from archaeological sites presents a mixture of ecological indicators, its components presently inhabiting different natural zones. The sediments studied at the Bol'shoi Naryn and Gerasimov's sites and dated to MIS 3 yielded fauna with a large proportion of tundra species; its composition suggests mosaic landscapes of tundra-forest-meadow-steppes and a cold humid climate at the time of human habitation. Fauna from the Malta site (MIS 2) is indicative of tundra-steppe and harsh climate at the beginning of the Sartan glaciation. Evidence from the end of the Pleistocene and postglacial, indicates the climate becoming warmer and wetter. Tundra animals are absent from MIS 3 sites of Transbaikalia. According to faunal evidence, dry steppe and arid climates existed at the early Sartan (MIS 2), and taiga animal species appeared and increased in importance towards the end of Pleistocene, when the forests had wide distribution. Fauna from MIS 3 sites in the southwestern Baikal area (Near-Baikal area) is similar to Transbaikalia, lacking tundra species and dominated by indicators of dry steppe and arid climates. The southwestern Baikal is more similar to Fore-Baikal area, both having a higher proportion of forest species than in Transbaikalian assemblages. The fauna distribution displays features of mosaic landscapes with distinctly identified zones: forest- and meadow-steppe along rivers, and dry steppe and semi-desert on south-facing slopes of mountains. The climate was milder than in the Transbaikal and warmer than in the Fore-Baikal area. Unfortunately, we have little data on the fauna of MIS 2.

We had developed a unique porous thin films by a special coating method1. In this technique, two dielectric materials A and B having different refractive indices nA and nB ,where nA＞nB are simultaneously deposited in vacuum on a substrate such as fused silica or optical glasses. Then the coated surface is processed in ultra-pure water which preferentially dissolves the material B. These processes result in a porous thin film which has gradient refractive index and has the antireflection (AR) property over broad bandwidth. The porous coating obtained by this method cannot apply depositing a multilayered dielectric thin film. We have developed a novel method. The present technique, a dielectric material D and a plastic P are simultaneously deposited in vacuum on a heated-substrate such as fused silica, ceramic or optical glasses. Then the coated surface forms an adaptively mixed thin film ( AMTF ) with dielectric material and plastic. In this coating process, plastics partially evaporate due to the heated-substrate. The refractive index of the coated AMTF mainly decided by the mixing ratio of the dielectric material and plastic. In our samples the damage threshold was confirmed to be 115 J/cm2 at 10 ns and λ=1064 nm. The band width of AMTF with MgF2 and Teflon (AMTF: MgF2 ) was confirmed to cover from 200 to 8000 nm. This AMTF: MgF2 can be applicable not only to AR thin film, but to a high reflectance mirror and polarizer in various high intensity laser syetems. 1K.Yoshida, H.Yoshida, Y.Kato, and C.Yamanaka, Appl.Phy.Lett.47,911(1985)

Two pieces of lacquer obtained from Ryukyu lacquerwares produced in the 17–19th century in the Ryukyu Kingdom belonging to the Urasoe Art Museum were analyzed by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The results were compared with the standard of natural lacquer film to determine the identity of the lacquer species. Urushiol (MW = 320), 3-heptylcatechol (MW = 208), and 3-heptylphenol (MW = 192) were detected as pyrolysis products of lacquer pieces of a lacquer tray made by the hakue technique, suggesting that this Ryukyu lacquerware was coated with lacquer sap tapped from a Toxicodendron vernicifluum lacquer tree. On the other hand, urushiol (MW = 320), 3-heptylcatechol (MW = 208), 3-heptylphenol (MW = 192), laccol (MW = 348), 3-nonylcatechol (MW = 236), and 3-nonylphenol (MW = 220) were detected as pyrolysis products of lacquer pieces from a dinner tray made by the mitsuda-e technique, suggesting that this Ryukyu lacquerware was coated with mixture lacquer sap tapped from T. vernicifluum and Toxicodendron succedanea lacquer trees, respectively. Moreover, microscopy and cross-section studies demonstrated that the lacquers had a multi-layer structure. X-ray analytical microscopy was carried out directly on the surface of lacquerwares to determine the presence of different pigments.

As a result of integrated researches on two Paleolithic sites of the Fore-Baikal region – Bol'shoj Naryn and Gerasimov's, the first representative mammal fauna of the Karginian interstadial been dated and characterized. That provided the basis for reconstructing the paleoenvironments in the Fore-Baikal region during MIS 3. The species composition of the faunal remains recovered from the Bol'shoj Naryn site in the course of five-year excavations since 2003 was examined in details. Since 2010, the cultural layer was studied layer-by-layer (at 5 cm intervals), all the artifacts and faunal remains (of mollusks, birds, and mammals) being described. In addition, the lower, middle and upper parts of cultural layer were sampled for palynological analysis. The geological and paleontological data thus obtained suggest a moderately cold and humid climate in the Fore-Baikal region during MIS 3, with predominant open landscapes of steppes and relatively limited areas under taiga forest, tundra, and wetlands. There are abundant data on significant environmental changes in the Fore-Baikal region during MIS 3 previously obtained by investigators, such as pollen spectra recovered from the Lake Kotokel bottom sediments or faunal remains (including small mammals) excavated from the Bol'shoj Naryn site. The present study, however, differs from the earlier ones in that it included multidisciplinary analysis of a large number of faunal and floral remains recovered from the same section and characterizing the same region. The data thus obtained from the Bol'shoj Naryn site are extremely important for better understanding of the Late Pleistocene environments of the Fore-Baikal region.

Japanese Jōmon period lacquer-ware objects were analyzed using a digital optical microscope and pyrolysis gas chromatography–mass spectrometry. Comparison with standard lacquer films showed that all the objects were coated with sap tapped from Rhus vernicifera lacquer trees. Red iron oxide was used as a red pigment. Natural resin found in the lacquer pieces suggested that during the development of Japanese Jōmon lacquer-ware, lacquer workers used local lacquer resources to produce lacquer, and learned to use natural resin in the restoration and protection of the lacquer-ware objects. In addition, the production and technology of Jōmon lacquer-ware are also discussed.

This study measured radiocarbon dates of more than 30 samples of charred residues on pottery sherds of the Incipient stage of the Jomon period. The ages of potteries of Linear-relief (Ryukisenmon) were 15,300–13,700 cal BP, with great differences among remains. The pitted decoration (Enkomon), Nail-impressed (Tsumegatamon), and pressing and dragging (Oshibikimon) types indicate 13,800–12,400 cal BP. For pottery of the same type, differences among sites were large. At the Unokiminami site, the type of impressed cord mark (Oatsu jomon) is the main type, including Nail-impressed. The latter shows slightly older age. Stable isotope and elemental analyses were used to ascertain the origin of charred residues on the pottery. In the dataset of Jomon pottery of the oldest type, residues consisting only of cooked nuts were found. However, Jomon people, even from early times, are thought to have cooked mixed plant and animal ingredients, including marine products. DOI: 10.2458/azu_js_rc.55.16377

This study reconstructs food habits through carbon and nitrogen isotope analysis, and C/N analysis of charred residues inside pottery from Amur River sites in Russia (Goncharka 1 site, Novotroitskoe 10 site, Kondon 1 site) and in Hokkaido, Japan (Taisho 3 site, Yachiyo A site). We obtained dates from 12,330 to 7920 BP for these sites. There are major differences in the carbon and nitrogen isotope ratios between the Taisho 3 site (δ13C: -21.7 to -24.1; δ15N: 11.9–14.7%) and the other sites (δ13C:-22.0 to -27.1%; δ15N: 7.1–13.1%), suggesting that the people of the Taisho 3 site made use of anadromous fish such as salmonids and some species of trout, as well as marine resources. The dates from the other sites except Taisho 3 were assumed to be from a mixture of marine foods, C3 plants and terrestrial animals, and freshwater fish. The food boiled in the pots also indicated a high dependence on marine resources during the initial stages of the emergence of pottery.

We have fabricated a 410 x 468 mm size deformable mirror with 100 Bimorph piezoceramic actuators for the LFEX laser system at Osaka University. In the case of Bimorph-type deformable mirrors, the mirror surface had to be polished and coated after bonding the piezoceramic actuators to the rear side of the thin mirror substrate. This provides a good surface figure, but the coating temperature for the high-reflection mirror was strictly limited because of the thermal fragility of piezoceramic actuators. The mirror substrate with the actuators was polished, and an ion-assisted multilayer dielectric coating was produced at 60 degrees Celsius with our 80-inch coating chamber. The flatness of the mirror just after coating was 7 μm, and reduced by aging to 3.2 μm when the mirror was assembled. The surface figure of the assembled mirror with 20 piezostack bonded actuators is demonstrated and a laser-induced damage threshold tested with a witness sample is also reported.

In this study, molluscan shells housed at the University Museum, the University of Tokyo, provided a new set of region-specific correction values (ΔR) for the western Pacific, in particular for the central part of the main islands in the Japanese Archipelago and the southwest islands of Japan. The values of 40 total samples were calculated from 11 regions. North of the main islands and in the Ryukyu Islands, the mean ΔR values showed comparatively small values, 5–40 14C yr; in the central part of the main islands, these values were 60–90 14C yr.

北海道駒ヶ岳火山北西～北東山麓部に露出する噴出物の層序，14C年代，岩石学的特徴を検討した．これまで40～6 cal kaの間には4層の噴火堆積物が識別されていたが，今回新たに7層の噴火堆積物（P7～P1）を識別した．それらの噴火年代は，約19 cal ka（P7），約17.7 cal ka（P6），約17.4 cal ka（P5），約14.8 cal ka（P4），約12.8 cal ka（P3），約6.5～6.3 cal ka（P2，P1）である．北海道駒ヶ岳火山の活動は，6,000年以上の長い休止期によって少なくとも4つの活動期（39 cal ka 以前, 20～12.8 cal ka, 6.8～6.3 cal ka, 1640 AD以降）に区分される．これら4つの活動期は本質物質の全岩化学組成も異なっている．最近3回の活動期は，4～6回のマグマ噴火からなり，規模の大きな噴火で始まり，その後より規模の小さい噴火を繰り返していたことが明らかになった．

We performed U–Th radioactive disequilibrium analyses of carbonate nodules and sediment samples recovered from methane seep sites off Joetsu, of the eastern margin of Japan Sea, to decipher the active period of the methane seep. The carbonates contain 230Th, part of which is located in detritus such as silicate and organics, at the time of precipitation. The initial 230Th renders accurate dating with U–Th radioactive disequilibrium method difficult. We assessed the feasibility of correction using radioactive disequilibrium data of ambient sediment to overcome this difficulty. A (230Th/232Th)–(234U/232Th) isochron drawn by three chips divided from a carbonate nodule (PC05-04-50) passed through data points of local sediments. We conclude that the problem of initial 230Th can be resolved by measurements of local sediments. Results show that carbonate nodules include local sediment as impurities. Furthermore, the results of trace element analyses such as Rb, Zr, Nb, REE, Pb, and Th also support the idea. In all, 18 carbonate samples were dated with correction of initial 230Th using the mean value of local sediment in this study. The U–Th correction ages show 12–35ka with an isochron age of 26 ± 3ka. Results indicate that during the time interval of U–Th ages, from 12ka to 35ka, environmental conditions must have been favorable for enhanced methane flux through sediment. The extensive methane flow period at 20ka accords with the lowest-stand sea level during the last glacial age. Results of this study also suggest that U–Th ages of carbonate are useful as a reliable chronometer with regard to methane seep activation. In order to acquire U–Th ages of carbonate at methane seep sites, however, it is important to evaluate the amount of initial 230Th accurately using the value of sediment.

Located at approximately 53°N, 103°E, the Bol'shoj Naryn site lies on the hills facing Osa Bay, in the Bratsk Reservoir. The authors started excavating this site in 2003. By 2005, we had found 337 stone tools and flakes, and more than 600 animal fossils, from the paleosol layers ( 14 C dating: from 25,000 to 32,000 yr BP) deposited in the second half of the Karginian Interstadial. Large specimens of the fossils collected by visual observation were mostly the bones and teeth of Equus sp. and Bovinae, and small specimens obtained through wet sieving included many fossils of Lagurus lagurus , Microtus sp., and Spermophilus undulatus . This suggests that the steppe had spread around this site by the last half of the Karginian Interstadial. However, some of the animal fossils collected from the Bol'shoj Naryn site were characteristic of tundra or forest, as well as steppe. To understand why, remains characteristic of three different habitats were excavated from the same paleosol of the Karginian Interstadial, detailed discussions centered on the radiocarbon age of each material are needed. As part of our investigation of the fossils of large vertebrates, we measured various parts of the fossils of Eanus sp. in excavated specimens and in specimens collected from the reservoir's shore, in accordance with the procedure described by von den Driesch [1976. A Guide to the Measurement of Animal Bones from Archaeological Sites. Peabody Museum of Archaeology and Ethnology Bulletin 1, Peabody Museum, Harvard University, Cambridge, MA]. We inserted the measured values into the formula of Nishinakagawa et al. [1991. A study on the time and the route of the introduction of cattle and horses into Japan, as examined from skeletal remains of archaeological sites. Report of the Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology, Scientific Research (B) 1990 (Japanese, English abstract)] and found that the collected fossils were mostly of individuals with withers heights between 125 and 135 cm. To clarify the time transition, a future project will use measurements to examine the trait characteristics of the fossils of other large mammals. In future, we intend to clarify the histories of nature and humankind in the Pleistocene in the Fore-Baikal region and to add animal fossils excavated from other sites to the scope of our research.

A new type of solar pumped laser system that has features of high-efficiency and low cost due to the use of a Fresnel lens and a Cr codoped Nd:YAG ceramic laser medium is reported in this paper. Slope efficiencies of 7 to 9% have been achieved. The laser output of about 80 W was achieved with the combination of a 4-m2 Fresnel lens and solar light chamber as a secondary power concentrator. The maximum output from a unit area of the Fresnel lens was 20 W/m2, which is 2.8 times larger than the previous results with a mirror type concentrator.

In order to obtain precise and accurate calibrated radiocarbon chronologies for archaeological sites, it is necessary to determine the provenance of the carbon material being dated. Of particular note is determining the provenance and radiocarbon age of charcoal remains on pottery. In this context, we discuss the decipherment of dates on the Ustinovka-8 site in the Russian Far East. Using δ13C, δ15N and C:N it is possible to ascribe charcoal provenance to terrestrial and marine origins. Our data show radiocarbon age difference that are clearly associated with carbon origin, and a maximum estimated ΔR of approximately 400 years during the Zaisanovskaya culture, 4400 cal BP. A combination of pottery analysis and 14C dating at this site determined the Zaisanovskaya cultural period to be 4000–5000 cal BP, the Boismanskaya and the Late Rudninskaya cultural period 5800–6500 cal BP, and the Early Rudninskaya cultural period of 6800–7100 cal BP.

Apparent 14C ages of the pre-bomb molluscan shells show new estimations of ΔR values for the western Pacific including the East Sakhalin Current, Oyashio Current, Kuroshio Current, Kuroshio Countercurrent, and Pacific North Equatorial Current. Clear differences in ΔR between the subarctic and subtropical gyres water masses around the Japanese archipelago are observed.

We investigated various defects of the organic 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystal to improve its laser-induced-damage tolerance for high-power terahertz (THz) application. We used DAST crystals grown by the slow-cooling method in methanol solution, and an irradiated infrared laser with a wavelength of 1550 nm without DAST absorption. It was found that laser damage was easily caused by crystal defects such as a rough surface, twin boundaries, and narrow-line defects (NLDs) in the bulk. In particular, NLDs are a serious problem that degrade the bulk laser-induced-damage tolerance of DAST crystals. The DAST crystals without such defects have high laser-induced-damage tolerance. To suppress the formation of crystal defects, we modified the crystal-growth conditions, and succeeded in growing DAST crystals with fewer defects than crystals obtained by the conventional growth process.

Growth of twin-free and high-quality 4-N,N-dimethylamino-4‘-N‘-methyl stilbazolium tosylate (DAST) crystals, with a surface roughness in the range of 1.7−3.8 nm (

▪ Abstract Yttrium aluminum garnet (YAG) (Y3Al5O12) single crystals doped with active species such as Nd and Yb have been used as laser media in solid-state lasers requiring high energy and excellent beam quality. This is because single crystals have extremely high thermal mechanical properties and optical qualities and because they enable high-efficiency laser oscillation. In 1995 the authors, using polycrystalline Nd:YAG, demonstrated a high-efficiency laser that was comparable to a single-crystal laser. Subsequently, single-longitudinal-mode oscillation, green and blue laser oscillation, and ultrashort-pulse laser oscillation were reported. Using the ceramic powder approach, the authors developed a composite laser element with a complicated structure that could not be produced by crystal growth techniques. This review discusses problems of conventional single-crystal growth, the fabrication and characteristics of ceramic lasers, laser oscillation properties (continuous-wave and pulse operation), light-scattering sources in ceramics, and typical applications of ceramic lasers.

The dependence of the bulk damage threshold of nonlinear crystals, such as KDP, KTP, LBO, BBO, CLBO, LiNbO3, and LiTaO3 on laser irradiation direction and their polarization under a single-shot operation have been investigated. We found that the intrinsic bulk-damage threshold for nonlinear crystals was mainly caused by dielectric breakdown from self-focusing with nonlinear refractive index. LBO single crystals have the highest value studied among nonlinear crystals. For KDP, BBO, and CLBO crystals, the damage threshold when an incident laser was propagated along the axis is approximately twofold that in the {100} or {010} plane at a 1.064 µm wavelength. The damage crack pattern is also suggested to be in the mechanically weak direction due to inner pressure caused a laser-induced plasma in the crystal as a result of the laser breakdown due to electron avalanche breakdown.

越後平野中部を対象として, 層相や土砂の堆積速度の地域的差異を検討し, 完新世後期における河川供給土砂の堆積場の変化と地形発達を明らかにした. 同地域では縄文海進時に内湾が形成され, 7,000～6,000yrsBPには湾奥部にまで海水の影響が及んだ. 縄文海進高頂期以降, 内湾は縮小と拡大を繰り返しながら, 信濃川の供給土砂によって徐々に埋積された. 土砂の堆積場の中心は, 完新世後期を通じて海側に移行する傾向が認められ, 4,000yrsBP以降には臨海部における土砂の前方付加や砂丘の形成が集中的に進行した. 一方, 堆積場の中心から外れた内陸側の氾濫原においては, 土砂の垂直的な堆積が徐々に進行し, その過程においては河川の洪水による土砂の堆積が少ない1,400～1,000yrsBPの「安定期」と, 土砂の堆積が活発化した1,000～800yrsBPの「堆積期」が認められた. 現在, 西川と中之口川の間の氾濫原にみられる自然堤防群の大半は, 1,000～800yrsBPに生じた河川の洪水による土砂堆積の活発化にともなって形成された.

This study revealed a promising method for removing positive-tone diazonaphthoquinone/novolak resist. The fourth harmonic of an Nd 3þ :YAG (Y3Al5O12) pulsed laser (266 nm) was irradiated onto the resist. Resist was removed when laser power exceeded 35 mJ/cm 2 , and a 250 nm-thick resist was removed with a laser power of 94 mJ/cm 2 . X-ray Photoelectron Spectroscopy (XPS) proved that 1100 nm-thick resist could be completely removed from a Si surface when it was irradiated almost 700 mJ/cm 2 . The resist onto three inch Si wafer (45.58 mm 2 ) was removed in two minutes by laser. No damage to the processed Si wafer could be detected by optical microscopic observation. This method is good for environment. (DOI 10.1295/polymj.37.813)

For the present study, 1.1-at.%-Nd-doped YAG ceramics with controlled amounts of grain-boundary phase were fabricated by a solid-state reaction method using high-purity powders. The optical scattering loss of the Nd:YAG ceramics, obtained from Fresnels equation, increased simply with increased amounts of grain-boundary phase. The continuouswave laser output power of the Nd:YAG ceramics clearly was related to the scattering loss coefficients of the specimens that, in turn, were affected by the amount of grain-boundary phase. Although the scattering loss coefficients of Nd:YAG ceramics with grain-boundary-free structure and a lower pore volume (}150 vol ppm) were almost equivalent to those of a 0.9-at.%-Nd-doped YAG single crystal grown by the Czochralski method, the laser output power of the Nd:YAG ceramics exceeded that of the Nd:YAG single crystal with increased exciting power under excitation with an 808 nm diode laser because of the large amount of neodymium additives. Lasing performance was not affected by the existence of grain boundaries in the polycrystalline specimen.

Calcium fluoride single crystals for next-generation optical lithography were fabricated with surfaces corresponding to the (001), (111), and (110) crystalline planes. The grinding process utilized an ultra-precision surface grinder and was optimized for resin-bonded SD3000-75-B diamond wheels. A premium crystalline surface had a measured surface roughness of 0.89 nm Ra, 6.99 nm Ry and 1.10 nm rms, with no microcracks. We show that the surface roughness of these samples depends on the crystalline plane and the orientation, as well as on the grinding conditions. Measurement of the sub-surface damage layer and the laser-induced damage threshold are also presented herewith.

This study developed a new method for removing positive-tone diazonaphtho- quinone/novolak resist. The fourth harmonic wave (l=266nm) of a pulse Nd3+:YAG laser was used. Ablation occurred at the resist surface when it was irradiated with over 35mJ/cm2. The amounr of removed resist increased with an increase in the laser energy, and it was possible to remove a 250nm thick resist layer by one pulse irradiation with 94mJ/cm2. Resist with an initial thickness of 1100nm and could be completely removed with no damage to the Si wafer after being irradiated seven times with 94mJ/cm2. The XPS measurement indicated that the residual amount of carbon from the Si surface irradiated by a laser under the vacuum was almost same to that from a Si wafer without resist coating. Resist removal method by laser is environmentally sound and will contribute to energy reduction.

Direct dating of a potsherd itself has been investigated for one group of Jomon pottery, so-called `fiber-tempered pottery', which contain a large amount of organic fiber as a temper. The best condition of alkaline treatment is examined for four samples. Each sample was divided into two parts, the surface and the black inside. A fraction of humic acid alone can be removed when a suitable moderate condition. In this study, 14 potteries have been dated.

High purity calcium fluoride (111) single crystals were float polished to a flatness of 32 nm p-v on 90-mm-diameter samples that had a surface roughness of 0.72 nm Ry, and 0.077 nm rms, as measured with a Scanning Probe Microscope (SPM). By observing an area of a float-polished surface with a high resolution transmission electron microscope, it was determined that the float-polished surface had a perfect (111) lattice with small atomic steps, and no subsurface damage. The polished surface roughness depends on the mismatch between the sample surface and the (111) plane. This result was also verified by SPM observation.

Fused-quartz glass is found to be an ideal medium for high-power stimulated Brillouin-scattering experiments, because it gives a high reflectivity of over 95% at an incident energy of 2.3 J, has pulse duration of 16 ns, and has excellent fidelity in phase conjugation. The low optical homogeneity of the fused-quartz material selected resulted in a low focusability at the focus, resulting in a reduction in laser-damage occurrence, even in high-energy operations. Despite this fact, its conjugation fidelity is good for cancellation as a phase-conjugated mirror. All solid-state lasers with high-beam qualities, based on phase-conjugated mirrors with fused-quartz glass are highly suitable for use as laser sources in many applications.

Laser-supported propulsion of a micro-airplane with a water-covered ablator is demonstrated. The repetitive use of an overlay structure is experimentally demonstrated with a specially designed water supply. Various transparent overlays are investigated by the CIP-based hydrodynamic code and by experiments using a pendulum and using a semi-conductor load cell. A momentum-coupling efficiency of ∼104 N s/MJ is achieved by water–exotic-target experiments, in agreement with the simulation code, which predicts a maximum efficiency of ∼105 N s/MJ. The concept of laser-supported propulsion can also be used for driving a Mach 5 airplane in the stratosphere, a micro-ship inside the human body, and a robot in a nuclear power reactor accident, during which large numbers of neutrons make electronic devices useless.

The influence of crystal defects on bulk laser damage and UV absorption in CsLiB 6 O 10 (CLBO) crystals was investigated. A CLBO crystal grown by the solution stirring method had a 2.5-fold higher laser-induced damage threshold (maximum) than conventional CLBO crystals. This highly damage-resistant CLBO crystal had a lower dislocation density (best value, 6.6×10 3 /cm 2 ) than conventional CLBO crystals (best value, 15.0×10 3 /cm 2 ). The temperature increase during UV generation on the output surface of highly damage-resistant CLBzO crystal was lower than that detected in conventional CLBO crystal.

Non-linear hydrodynamic behavior of bubble motion and that of particle motion in a three-phase fluidized bed have been modeled by resorting to an artificial neural network (ANN). The experiments were performed in a transparent acrylic resin column with an inner diameter of 0.184 m and a height of 2.0 m. Subsequently, the ANN was trained with the time-series data comprising temporal intervals, each of which was the period between two sequential signals of bubbles or particles from an optical transmittance probe. By successively adapting its output to input, the ANN has regenerated time-series data at any superficial gas velocity, Ug, thereby yielding the bifurcation diagrams of both bubble and particle motion. These diagrams exhibit complex behavior over a wide range of Ug, thus demonstrating that the ANN is capable of predicting and modeling non-linear dynamics of three-phase fluidized beds often behaving chaotically.

Laser-supported propulsion of a micro-airplane with a water-covered ablator is demonstrated. The repetitive use of an overlay structure is experimentally demonstrated with a specially designed water supply. Various transparent overlays are investigated by the CIP-based hydrodynamic code and by experiments using a pendulum and using a semi-conductor load cell. A momentum-coupling efficiency of ∼104 N s/MJ is achieved by water–exotic-target experiments, in agreement with the simulation code, which predicts a maximum efficiency of ∼105 N s/MJ. The concept of laser-supported propulsion can also be used for driving a Mach 5 airplane in the stratosphere, a micro-ship inside the human body, and a robot in a nuclear power reactor accident, during which large numbers of neutrons make electronic devices useless.

A hard X-ray microbeam with submicrometer spot size from third-generation high brilliance synchrotron radiation (SR) sources is expected to be a powerful tool for various fields of research. A Fresnel zone plate (FZP) is one of the promising, focusing elements for X-rays. Focusing efficiency is one of the important features of the FZP. In order to fabricate an FZP with a high focusing efficiency, it is necessary to investigate the relation between the experimental values of the focusing efficiency and the theoretical ones. We have fabricated Ag/C and Cu/Al multilayer (sputtered-sliced) FZPs for use in hard X-ray region, and have compared the measured focusing efficiency data with the calculated ones. The experimental data have been in good agreement with the theoretical values.

Bulk laser-induced damage in KDP crystal was measured using a single-shot 1-ns pulse Nd:YAG laser in a transverse and longitudinal single mode. It is found that the damage threshold of KDP single crystal depends on the laser irradiation direction, polarization direction and laser wavelength. The damage threshold in the direction of c axis is about two times higher than that of in the a(b) axis at 0.532 and 1.064 μm wavelength. This result is consistent with the mechanical strength tests for various directions of KDP crystal.

The nonlinear dynamics of a gas–solid circulating fluidized bed (CFB) was characterized by the correlation dimension and Kolmogorov entropy of time series of three different system variables with different spatio-temporal scales. Fluctuations of pressure, local bed voidage and heat transfer rate were simultaneously measured by a pressure transducer, an optical transmittance probe and a hot wire probe, respectively, at different axial and radial positions in the riser of 10 m height and 0.1 m i.d. The pressure fluctuation reflected the global hydrodynamic behavior of the CFB and was found to exhibit uniform distributions of the correlation dimension and the Kolmogorov entropy along the riser independent of the circulating solid flux. On the other hand, the correlation dimension and Kolmogorov entropy of local heat transfer and local voidage fluctuations significantly depended on circulating solid flux and axial and the radial positions, reflecting the small-scale spatio-temporal patterns of gas–solid flow induced by cluster and individual particle motions.

Local voidage fluctuations have been measured by using an optical transmittance probe at various axial and radial positions in a circulating fluidized bed riser with a 0.1 m i. d. and 10 m height. The chaotic time series analysis of the local voidage fluctuations has been adopted to characterize the nonlinear dynamics of the circulating fluidized bed riser. The variations of the correlation dimension and the Kolmogorov entropy of the voidage fluctuation were found to depend on the local time-average voidage. The axial and radial distributions of the correlation dimension and the Kolmogorov entropy were strongly affected by the solids flow structures (e.g. core-annulus flow) in various operating conditions. The correlation dimension of local voidage fluctuations increases along the riser, except the position near the distributor. Both, the correlation dimension and the Kolmogorov entropy of local voidage fluctuations near the wall, were found to be smaller than those at the center of the riser, independent of the solids circulation rate and the axial position. Des fluctuations de vides locales ont ete mesurees a I'aide d'une sonde de transmittance optique a differentes positions radiales et axiales dans une colonne a lit fluidise circulant de 0,1 m de diametre interieur et 10 m de hauteur. On a eu recours a I'analyse par series temporelles chaotiques des fluctuations de vide locales pour caracteriser la dynamique non lineaire de la colonne montante a lit fluidise circulant. On a trouve que la dimension de correlation et I'entropie de Kolmogorov de la fluctuation de vide dependaient du vide moyenne dans le temps local. Les distributions axiales et radiales de la dimension de correlation et de I'entropie de Kolmogorov ont ete fortement influences par les structures d'ecoulement des solides (p. ex. ecoulement coeur-espace annulaire) dans differentes conditions de fonctionnement. La dimension de correlation des fluctuations de vide locales augmente le long de la colonne montante, sauf pres du distributeur. On a trouve que la dimension de correlation et I'entropie de Kolmogorov des fluctuation de vide locales pres de la paroi etaient toutes deux plus petites que celles observees au centre de la colonne, independamment de la vitesse de circulation des solides et de la position axiale.

Proposed is GLLL2, a hybrid architecture of a global and a local learning module, which learns default and exceptional knowledge respectively from noisy examples. The global learning module, which is a feedforward neural network, captures global trends gradually, while the local learning module stores local exceptions quickly. The latter module distinguishes noise from exceptions, and learns only exceptions, which makes GLLL2 noise-tolerant. The results of experiments show the process in which training examples are formed into default and exceptional knowledge, and demonstrate that the predictive accuracy, the space efficiency, and the training efficiency of GLLL2 is higher than those of each individual module.