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1.
The selection of a non-shattering phenotype is a pivotal change in the process of rice domestication. However, current research is heavily restricted by the preservation conditions of macro-plant remains in early and middle Neolithic sites, as very limited well-preserved rice spikelet bases could be retrieved. We present a non-destructive method based on micro-computed tomographic (CT) scanning, which could provide detailed visualization of the internal structures of charred spikelet bases and efficiently discriminate the shattering and non-shattering phenotypes of rice spikelet bases according to the abundance of fusiform echinate phytoliths. It could be widely applied in different contexts, especially those poorly preserved specimens and tempers in pottery sherds, greatly improving our knowledge of rice domestication.  相似文献   
2.
A human skull, buried about 2500 years ago in a Bronze Age cemetery at Jinggouzi, a site of an important ethnic group in ancient China, appeared to have characteristics of fibrous dysplasia. The CT images indicated a reduction in bone density and relatively homogeneous lesions. More features were revealed using CT reconstruction techniques. Lesions seen in low‐magnification images using a 3D deep‐field microscope had an irregular honeycomb‐like structure. At higher magnification, the trabeculae morphology and the gaps between the trabeculae were irregular and varied in size and shape. Paraffin‐embedded specimens stained with HE showed trabeculae with tortuous irregular arrangements varying in shape and width. The irregular trabeculae of woven bone has been described as having fibrous dysplasia. Molecular analysis of the GNAS gene indicated no mutation. This provides a non‐invasive approach for us to make more comprehensive diagnoses and to assist research into ancient human diseases.  相似文献   
3.
Capillary trapping is a physical mechanism by which carbon dioxide (CO2) is naturally immobilized in the pore spaces of aquifer rocks during geologic carbon sequestration operations, and thus a key aspect of estimating geologic storage potential. Here, we studied capillary trapping of supercritical carbon dioxide (scCO2), and the effect of initial scCO2 saturation and flow rate on the storage/trapping potential of Berea sandstone. We performed two‐phase, scCO2‐brine displacements in two samples, each subject to four sequential drainage–imbibition core‐flooding cycles to quantify end‐point saturations of scCO2 with the aid of micro‐ and macro‐computed tomography imaging. From these experiments, we found that between 51% and 75% of the initial CO2 injected can be left behind after the brine injection. We also observed that the initial scCO2 saturation influenced the residual scCO2 saturation to a greater extent than the rate of brine injection under the experimental conditions examined. In spite of differences in the experimental conditions tested, as well as those reported in the literature, initial and residual saturations were found to follow a consistent relationship.  相似文献   
4.
This case study was the first of its kind, where neutron computed tomography (CT) was applied to a wrapped mummified animal. Conventional X‐ray CT was also used to allow for meaningful comparison, and complementary data for a comprehensive investigation. Previous applications of both techniques are limited to metallic objects, such as bronze Buddhas. The mummy used in this study (IA.2402) is dated between the Third Intermediate Period (1069–664 bce ) to Late Period (664–332 bce ) according to the wrapping style, and was originally believed to contain a complete skeleton of a feline. However, precise date and provenance were unknown. Our results prove the presence of only partial juvenile feline remains, and provide a date range for artefact creation (900–804 bce ± 30) and alteration (367–204 bce ± 30). Therefore, this study implements an established imaging technique (neutron CT) in a novel way, while preserving and conserving the intrinsic value of the artefact through non‐destructive investigation.  相似文献   
5.
非均质的砂砾石层是莫高窟壁画的主要墙体,但砂砾石层的非均质性如何在水盐运移过程中发挥作用却还不清楚。为此,通过在108窟西壁面上1 m×1 m和2 m×2 m范围的三维高密度电阻率成像监测,发现在这些区域上,墙体电阻率的空间分布都是非均匀的,低阻值区域在空间位置、大小和形状上都会随时间而变化。这明确说明在构成墙体的非均质砂砾石层内存在着重要的水分饱和与非饱和过程(再分配过程),正是这一不断重复的饱和与非饱和过程促进了墙体内水分的运移和盐分在一些特定区域的聚集。研究成果对全面认识莫高窟墙体内的水盐运移机理,减轻和防治壁画盐害都具有重要意义。  相似文献   
6.
Timber structures can be degraded during their life both by structural problems and by biological degradation factors like fungi and insects. The occurrence of those biodegradation agents could lead to a loss of their structural integrity, in the absence of appropriate maintenance. An early assessment of the decay is even more important when the wooden structures are part of historical buildings, in the interest of conservation of cultural heritage.

This article presents an application of microwave reflectometry for the in situ evaluation of timber structures. The measurement system allows detecting anomalies inside the material in a non-destructive and non-invasive manner.

The reflection coefficient is measured by means of a vector network analyzer (VNA) using a double-ridge antenna which transmits the continuous-wave (CW) microwave signal and receives the signal reflected by the material under investigation.

Measurements on laboratory models demonstrated the feasibility of the method. Results obtained on timber beam sections, compared with the findings of traditional investigation methodologies, demonstrate the potentiality of microwave reflectometry, suggesting its possible usefulness during the diagnostic phase as a non-invasive tool for preliminary screening.  相似文献   

7.
8.
Accurate bone density data are essential for assessing the influence of destructive processes in archaeological faunal assemblages. Unfortunately, the diversity of methods employed by different researchers to derive density values has resulted in recent confusion. Two recent publications in this journal [J Archaeol Sci 29 (2002) 883; J Archaeol Sci 29 (2002) 979] exemplify this state of misunderstanding. Both studies argued that the role of bone density in shaping archaeological faunal assemblages has been largely overrated, but both based their conclusions on density values that were inaccurately derived. The former employed a method of calculating bone density that has been largely discredited over the past decade [J Archaeol Sci 29 (2002) 883]. Within a larger discussion of zooarchaeological methodology, the latter provided an assessment of the current state of bone density research that inappropriately characterized the discrepancies between available sets of density data as a reflection of the differences between two technologies—photon densitometry and computed tomography [J Archaeol Sci 29 (2002) 979]. The actual dichotomy exists—irrespective of the technology employed—between studies that account for variation in the shape of bone cross-sections and those that do not. The different sets of density data currently available to zooarchaeologists vary tremendously in their accuracy. We review and evaluate the different techniques employed in the research of bone density patterns of mammalian fauna. Computed tomography produces the most accurate density data. For elements without medullary cavities, photon densitometry may provide density values of similar accuracy but only if a method of cross-sectional shape-adjustment is applied.  相似文献   
9.
The number of computerised tomography (CT) investigations of mummies has increased since the first published study in 1979. However, this approach has never been validated. We present a critical analysis of the literature (1979 to 2005). Relevant articles were selected via a MedLine search and analysed according to CT technique, methodology, and author's speciality. Thirty‐one original articles matched our selection criteria. Of these studies, 42% were authored by radiologists, while 26% had no contribution from radiologists. Hypothesis‐driven papers comprised only 9.7% of the total. While 84% of the studies had a stated purpose for conducting the CT study, only 67% of studies defined their CT protocol clearly. CT was used to study mummification techniques in 74% of instances, and/or to detect disease in 58%. Conclusions based on CT analysis were derived in 84% of studies, but only 32% of these answered specific questions. Furthermore, only 36% of these conclusions were related to the stated purpose of the study. Using the criteria of the grading system we developed, we found that 61% of studies were supported only by weak evidence. We conclude that evidence‐based research with better design should be encouraged in future palaeoradiological studies. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
10.
Notwithstanding the relative abundance of bioarchaeological evidence of pre‐20th century gunshot wounds discovered at European and American archaeological sites, similar findings in East Asian countries have been very rare. In this study, we report evidence of possible gunshot wounds sustained by two individuals buried in Joseon tombs of Korea. The shapes of the trauma seemed to indicate low‐velocity projectiles, most likely musket balls. To our knowledge, this is the first bioarchaeological report specifically concerning possible gunshot‐wound evidence in East Asian skeletons recovered from archaeological fields. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
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