Steepening of reflectivity structures detected in high-resolution Doppler spectra of polar mesosphere summer echoes (PMSE) observed with the EISCAT 224 MHz radar

Polar mesosphere summer echoes observed with the EISCAT 224 MHz radar frequently exhibit significant discontinuous offsets or jumps in the Doppler frequency. We can explain these frequency jumps as a result of a lifting of partially reflecting or scattering layers, which are distorted by bumps. These bumps can be caused by steepened refractivity variations, i.e. reflectivity structures. These suggestions are supported by model computations. We also notice that a relation exists between these structure shapes and gravity waves, which are steepened, but which do not necessarily break into enhanced turbulent velocity fluctuations.     

VHF radar observations of nonlinear interactions in the summer polar mesosphere

VHF radar measurements of velocities and echo power in the summer polar mesosphere have been analysed using maximum entropy, bispectral and cross-spectral methods in order to study wave-wave interactions. The results show nonlinear interactions of second and even third order between the diurnal and semidiurnal tides and planetary waves with periods of 2 and 3 days in the velocity field. Similar analyses of time series of echo power suggest corresponding variations of the temperature field.     

Some characteristics of the quiet polar D-region and mesosphere obtained with the partial reflection method

It is shown that from a detailed analysis of the amplitude behaviour of electromagnetic waves partially reflected in the D-region valuable information about the reflection process and the dynamics of the mesosphere can be obtained. The results indicate that the process which is responsible for the partial reflections is different for different heights in the D-region and also changes with the season. From the temporal fluctuations of the amplitudes of the reflected waves, estimates of various turbulence parameters of the mesosphere have been deduced. Their mean values are in satisfactory agreement with results obtained by other methods.     

Long period wind oscillations observed by the Kyoto meteor radar and comparison of the quasi-2-day wave with Adelaide HF radar observations

We have detected wind oscillations with periods ranging from 1.4 to 20 days at 80–110 km altitude using Kyoto meteor radar observations made in 1983–1985. Among these oscillations, the quasi-2-day wave is repeatedly enhanced in summer and autumn. We found that the period of the quasi-2-day wave ranges from 52 to 55 h in summer, and becomes as short as 46 to 48 h in autumn in 1983 and 1984. The change in the wave period seems to coincide with a decrease in the amplitude of the zonal mean wind. A quasi-2-day wave event was simultaneously observed in January 1984 at Kyoto (35° N, 136°E) and Adelaide (35° S, 138° E), which are located at conjugate points relative to the geographic equator. Amplitudes of the meridional component at Adelaide are approximately four times larger than those observed at Kyoto. Comparison observations clearly show that the meridional component is in phase and the zonal component is out of phase, respectively, implying antisymmetry of the quasi-2-day wave between the northern and southern hemispheres. Relative phase progressions with height are similar between the Kyoto and Adelaide results for both meridional and zonal components, and indicate the presence of an upward energy propagating wave with a vertical wavelength of about 100 km.     

Dominant vertical scales of gravity waves in the middle atmosphere observed with the MU radar and rocketsondes

We have simultaneously observed wind motions in the altitude range of 5–90 km by means of the MU radar, rocketsondes and radiosondes. Dominant vertical scales of wind fluctuations due to gravity waves were 2–5 km in the lower stratosphere, about 5–15 km in the upper stratosphere and longer than 15 km in the mesosphere. The increase in the vertical scale with altitude is interpreted in terms of the saturation of upward propagating gravity waves. In the stratosphere, the observed vertical wavenumber spectra showed smaller amplitudes and more gradual slopes than the model values. Furthermore, the wind velocity variance in the stratosphere increases exponentially with an e-folding height of about 9 km, implying that the gravity waves were not fully saturated. On the other hand, the spectra in the upper stratosphere and mesosphere agreed fairly well with the model spectra. The variance in the mesosphere seems to cease increase of the wave amplitudes and agrees reasonably well with the model value.     

Integrated seismic tomography and ground-penetrating radar (GPR) for the high-resolution study of burial mounds (tumuli)

The study primarily aims at providing adequate imaging resolution of large and prominent targets of archaeological interest, such as pyramids and tumuli, at all depth levels. We implemented an integrated seismic tomography and georadar (STG) technique to perform high-resolution imaging and characterization of tumuli (burial mounds). We tested the proposed technique on a preserved late Bronze Age burial mound in northern Italy, for which STG succeeded in performing an accurate 3-D reconstruction of the structure and stratigraphy as proved by later archaeological excavations. We completed two transmission seismic tomography measurements, at present ground level and at 1.5 m elevation, with a 24-channel seismograph and 15° angular separation between geophones. The ground-penetrating radar (GPR) dataset encompasses 12 250 MHz radial profiles and 12 common mid point gathers for velocity analysis. Shallow layers of the mound are successfully imaged by GPR, whilst the structure of the deep central part of the tomb is reconstructed from seismic traveltime inversion. In particular, GPR images lenses and layers of sediments forming the external part of the tumulus, evidences of a looting attempt, peripheral structures associated with later exploitation of the mound (furnaces) and, in the external sector of the tumulus, the top of the deep layer of silty sediments covering the funeral chamber. Tomographic results reveal seismic velocity anomalies of potential archaeological interest at ground level, which were successively validated by archaeological excavations. The integration of GPR and tomographic datasets is an effective strategy to overcome the imaging and interpretation problems related to the structure of such peculiar funeral monuments. STG can be applied to a virtually unlimited dimensional range and requires a limited data acquisition, processing and inversion effort. The results of the study allowed the identification of the funeral chamber and a detailed imaging of layering and structural details.     

IMF effects in the appearance of slant E conditions (SEC) in the northern and southern polar regions

Vertical sounding data of the polar ionosphere are used to study slant E condition (SEC) related to the development of instabilities in the ionospheric plasma. The measurements from three Arctic and three Antarctic stations located correspondingly in the polar cap, daytime cusp and auroral zone are analyzed. It is shown that the SEC daily variations in these three regions are different. Distinctions between SEC features in the opposite hemispheres are affected by the azimuthal and vertical interplanetary magnetic field (IMF) components.     

The generation and propagation of atmospheric gravity waves observed during the Worldwide Atmospheric Gravity-wave Study (WAGS)

During the Worldwide Atmospheric Gravity-wave Study (WAGS) in October 1985, the EISCAT incoherent scatter radar was used to observe the generation of atmospheric gravity waves in the auroral zone in conjunction with a network of magnetometers and riometers. At the same time a chain of five ionosondes, an HF-Doppler system, a meteor radar and a radio telescope array were used to monitor any waves propagating southwards over the U.K.The EISCAT measurements indicated that in the evening sector both Joule heating and Lorentz forcing were sufficiently strong to generate waves, and both frequently showed an intrinsic periodicity caused by periodic variation in the magnetospheric electric field.Two occasions have been examined in detail where the onset of a source with intrinsic periodicity was followed by a propagating wave of the same period which was detected about an hour later, travelling southwards at speeds of over 300 m s⁻¹, by the ionosondes and the HF-Doppler radar. In both cases the delay in arrival was consistent with the observed velocity, which suggests a direct relationship between a source in the auroral zone and a wave observed at mid-latitude.     

Permanent monitoring of the upper mesosphere and lower thermosphere wind fields (prevailing and semidiurnal tidal components) obtained from LF D1 measurements in 1991 at the Collm Geophysical Observatory

The wind field of the upper mesosphere and lower thermosphere region (85–105 km) over Central Europe (52°N, 15°E) has been continually and reliably recorded by regular daily D1 radio wind measurements in the LF range (177, 225 and 270 kHz) using commercial radio transmitters. These measurements show the prevailing winds, the tidal wind components and the effects of internal gravity waves, as well as the seasonal and irregular variations of these parameters. The height of the wind measurements is determined by measuring the travel time differences between corresponding modulation bursts in the sky wave and in the ground wave. Using a quasi-online calculation procedure, the results are available immediately. Therefore they are useful for monitoring the upper atmospheric circulation with regard to upper atmosphere meteorology in the future. Vertical profiles of the wind field parameters can be derived with the aid of the combined wind and height measurements. Height-time cross-sections of the monthly mean prevailing winds and semidiurnal wind components have been calculated almost continuously for the last 10 years. The present paper deals with recent results for the year 1991.     

Study of medieval glass fragments from Savona (Italy) and their relation with the glass produced in Altare

Altare was in the medieval and post-medieval period an important glassmaking center in the Liguria region in Northern Italy. The first historical evidence of glassmaking in Altare is dated to the twelfth century. In spite of that, due to the continuity of glassmaking up to the present time and the contemporaneous intensive urbanization of the territory, no medieval glass from Altare or its immediate vicinity has been analyzed up to now. In this work, glass from archaeological excavations in the center of Savona, city with close ties with the glassmaking center, was studied. Glass fragments, dated from the tenth to the sixteenth century were selected from the collections of the Archaeological Museum in Savona and non-destructively analyzed with quantitative PIXE-PIGE. The resulting compositions, compared with known glass productions of the same time and evaluated on the basis of historical documents, offer an interesting panorama on the variety of glass circulation in Liguria.     

论“苏州片”失蜡铸造工艺的特色及其价值

"苏州片"是我国传统失蜡铸造的代表性工艺,以其法制作的仿古铜器,以精绝、乱真闻名于世,研究者与苏州艺人经数年的密切合作,成功复原此工艺。"苏州片"仿古铜器工艺蜡料配方独特、制范技艺考究、制作过程精细缜密,不仅具有历史人文价值,而且具有一定的经济、科技价值。传统手工艺要揭示其科学内涵,保护传承的同时注重创新,紧跟时代特色,走向产业化,才能在现代社会赢得生存空间。     

The origin and evolution of the concept of mixin (superstition): A review of May Fourth scientific views

ABSTRACT

This article explores the evolving connotations of the concept of “superstition” up to the establishment of “superstition studies,” in an examination of the process of secularization experienced by early modern Chinese thought under the impact of Western science. In traditional texts, the Chinese term mixin (迷信, literally “delusional beliefs”), modernly translated as“superstition,” carries diverse and variable meanings: aside from referring to the proper or improper content of ideas and beliefs, mixin also has political connotations, broadly referring to beliefs or behaviors differing from the official rituals. On an ideological level, the traditional concept of mixin refers to a category of thought opposed to Confucian concepts such as the cosmology of Heaven, Earth, and Man, or the idea that “for a man to sacrifice to a spirit which does not belong to him is flattery.” In the late Qing Dynasty, as the idea of “superstition” as opposed to “science” was introduced via Japan, the traditional connotations of mixin evaporated, and it merged with other neologisms. From the late Qing to the early Republic, the parameters of “superstition” were expanded to encompass anything at odds with “reason.” This was also a reflection of China’s shift from the “Classical Age” to the “Age of Science,” as Confucian concepts and scientific ideas successively served as the criteria for judging “superstition.” As of the present, a consensus has yet to be reached on how to distinguish between “religion” and “superstition.” This paper shall seek to clarify the connotations of mixin or “superstition” in different contexts and their connection to the changing times, which may aid in understanding the complex facets of this issue.     

Provenance of Early Bronze Age metal artefacts in Western Switzerland using elemental and lead isotopic compositions and their possible relation with copper minerals of the nearby Valais

Ten Early Bronze Age (BzA1, 2200–2000 BC) copper artefacts from the central Valais region from Switzerland were studied for their elemental composition and lead isotope ratios. In order to answer the archaeological question of a local copper supply, a database for copper minerals across the Valais (Switzerland) has been established. This database contains 69 data on lead isotope ratios as well as additional information on the minerals and geochemical associations for copper minerals from 38 locations in the Valais. Comparisons of the artefacts were also made with data pertaining to minerals from various deposits from Europe and Anatolia taken from the literature. The provenance of the materials is very diverse. Some of the data are compatible with the data from the copper mineral deposits of the Valais region. Moreover, three copper lunulae were identified as possibly Tuscan, which suggests contacts between Italy and the Valais region. This pattern also establishes a multiplicity of provenances for the metal and cultural influences in the Alpine environment of the Rhone Valley of Switzerland at the beginning of the Early Bronze Age.     

Holocene hyrax dung deposits in the afroalpine belt of the Bale Mountains (Ethiopia) and their palaeoclimatic implication

Abstract

The results of pollen analysis and radiocarbon dating are presented for two hyrax dung deposits from rock shelters found in the Afroalpine zone of the Bale Mountains (South-Central Ethiopia). Deposits accumulated from about 15,000 to 1500 (cal) years BP and from 7000 (cal) years BP till nowadays, respectively. Pollen spectra of the initial stages of deposit development (up to 15,000 (cal) years BP) correlate with unfavourable conditions in the Late Glacial Maximum. The African Humid Period (AHP) (15,000–5000 (cal) years BP) is registered in this palaeoecological record as well as the Younger Dryas event (about 12,500 (cal) years BP). Upward shift of Afromontane forest belt and expansion of ericoid communities at high altitudes were characteristic of the Pleistocene/Holocene transition (about 10,000 (cal) years BP). The AHP which continues around 10,000 (cal) years BP after Younger Dryas, was interrupted by a dry episode around 8200 (cal) years BP. Principal aridisation trend during the last 5000 years was observed. Presumably the first traces of human activities in this area can be shown for up about 2500 (cal) years BP.     

略评《建德市志(1978～2005)》的编纂思路和特色

2008年12月,笔者应邀参加了《建德市志（1978-2005）》稿评议会。时隔年余,《建德市志（1978-2005）》出版,阅读以后,更感到该志经过评议会后精心的深加工。本文拟从几个断面入手,略评其编纂思路和特色。     

Susceptibility measurements,optical and X-ray analysis to explain the origin of archaeological magnetic anomalies in Tavoliere lowland (Southern Italy)

Since 2002 a non-invasive investigation integrating aerial photography and high-resolution magnetometry has been carried out for reconstructing extensive ancient settlements in Tavoliere lowland (Southern Italy). Relevant magnetic anomalies were detected in all the surveyed sites allowing a precise mapping of the buried structures over more than 150 ha. Next to this research susceptibility measurements, PXRD, XRF and optical analysis were also performed in order to explain the origin of the notable magnetization contrast between the anthropogenic structures and the embedding materials, generating the measured signals. This last study was accomplished, in 2006, in Monte S. Vincenzo site, a vast Neolithic village where the remotely sensed data were also used to guide some direct inspection. Trial archaeological excavations brought to light parts of C-shaped compounds, providing complete information on the geometry and location of the sources of magnetic signals. Profiting by the archaeological feedback, the susceptibility contrast between the soil filling the ditches and the calcareous substratum was assessed in situ. A synthetic model based on this information was created and compared with the experimental data. The infilling material was also sampled for laboratory analysis: the presence of several magnetic minerals (pyroxenes, monometric magnetite, haematite) was ascertained. Furthermore optical analyses showed different types of volcanic and igneous products such as pumices, melanite garnets and lava fragments. Geomorphological and archaeometric evidence allowed us to relate these materials to activity of the Mt. Vesuvius volcano. Eventually their possible spatial distribution was inferred from recent studies on ash transportation and deposition during explosive activity.     

Images of buried graves in Bayat,Afyon (Turkey) from high-resolution magnetic data and their comparison with preliminary excavations

Dedemezari necropolis, the site of our study, is located in the west of Turkey near Afyon. Archaeologists think that it belongs to the Middle Bronze age. A high-resolution magnetic survey identified buried material highly accurately. In particular, anomalies, which are transformed by the analytic signal method, clarify the observed magnetic anomalies. Magnetic surveying was applied in three different areas in this study. The map of analytic signal-transformed anomalies presented good results on preliminary excavation in trenches A and B. Two types of graves are found in the study area. One is made of clay and the second is carved in the rocks. Shapes of the buried graves are mainly cylindrical and elliptical. Most of the magnetic anomalies are elliptical and reflect the shape of the buried materials. Future excavations in Dedemezari necropolis will be able to be carried out more easily due to the known locations of the buried graves.     

英国对台湾地区的政策特点及原因浅析(1950-1960年)

在东西方冷战的背景下,英国对台湾地区的政策受到多方面因素的影响,是一个棘手且无法回避的敏感问题。20世纪50年代,英国对台湾地区的政策呈现“政经分离”的特点:政治上保守慎重,强调与台湾当局保持距离;经济上积极主动,努力促进双方贸易的发展。英国政府之所以采取这一政策,不仅考虑到台海局势的严峻性、复杂性,也受英国重商主义传统与灵活务实外交思维的影响。英国对台湾地区的“政经分离”政策,使其在兼顾自身政治与经济利益的同时,也加剧了台海局势的复杂性。