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山东兖州发现大泉五十双面石范 被引量:1
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作者 王登伦 鹿占华 魏淑玲 《中国钱币》 2003年第2期45-46,共2页
1987年秋,兖州市博物馆进行文物普查时,在新驿镇王楼村征集到两件大泉五十双面钱范.据了解这两件钱范是在村南沙坑中发现的,现介绍如下:
关键词 山东 兖州市 大泉五十双 古钱币 货币史 钱背 面范 考古研究
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Surface sediment diatoms from the western Pacific marginal seas and their correlation to environmental variables 被引量:5
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作者 黄玥 蒋辉 +3 位作者 Svante Bjrck 李铁刚 吕厚远 冉莉华 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第3期674-682,共9页
Diatom data of 192 surface sediment samples from the marginal seas in the western Pacific together with modern summer and winter sea surface temperature and salinity data were analyzed.The results of canonical corresp... Diatom data of 192 surface sediment samples from the marginal seas in the western Pacific together with modern summer and winter sea surface temperature and salinity data were analyzed.The results of canonical correspondence analysis show that summer sea-surface salinity(SSS) is highly positively correlated with winter SSS and so is summer sea-surface temperature(SST) with winter SST.The correlations between SSSs and SSTs are less positively correlated,which may be due to interactions of regional current pattern and monsoon climate.The correlations between diatom species,sample sites and environmental variables concur with known diatom ecology and regional oceanographic characters.The results of forward selection of the environmental variables and associated Monte Carlo permutation tests of the statistical significance of each variable suggest that summer SSS and winter SST are the main environmental factors affecting the diatom distribution in the area and therefore preserved diatom data from down core could be used for reconstructions of summer SSS and winter SST in the region. 展开更多
关键词 DIATOMS the western Pacific marginal seas environmental variables summer sea surface salinity winter sea surface temperature
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Ring Polymer Molecular Dynamics of the C(^(1)D)+H_(2) Reaction on the Most Recent Potential Energy Surfaces
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作者 Jianwei Cao Yanan Wu Wensheng Bian 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第6期833-842,I0003,I0004,共12页
Ring polymer molecular dynamics(RPMD)calculations for the C(^(1)D)+H_(2)reaction are performed on the Zhang-Ma-Bian ab initio potential energy surfaces(PESs)recently constructed by our group,which are unique in very g... Ring polymer molecular dynamics(RPMD)calculations for the C(^(1)D)+H_(2)reaction are performed on the Zhang-Ma-Bian ab initio potential energy surfaces(PESs)recently constructed by our group,which are unique in very good descriptions of the regions around conical intersections and of van der Waals(vdW)interactions.The calculated reaction thermal rate coefficients are in very good agreement with the latest experimental results.The rate coefficients obtained from the ground˜a^(1)A′ZMB-a PES are much larger than those from the previous RKHS PES,which can be attributed to that the vdW saddles on our PESs have very different dynamical effects from the vdW wells on the previous PESs,indicating that the RPMD approach is able to include dynamical effects of the topological structures caused by vdW interactions.The importance of the excited˜b^(1)A′′ZMB-b PES and quantum effects in the title reaction is also underscored. 展开更多
关键词 Rate coefficients Ring polymer molecular dynamics Complex-forming reactions Potential energy surfaces van der Waals interactions
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Traversing the singularity hypersurface by applying the input disturbances to 6-SPS parallel manipulator
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作者 Yu-tong LI Yu-xin WANG +1 位作者 Shuang-xia PAN Rui-qin GUO 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2008年第11期1539-1551,共13页
The singular points of a 6-SPS Stewart platform are distributed on the multi-dimensional singularity hypersurface in the task-space, which divides the workspace of the manipulator into several singularity-free regions... The singular points of a 6-SPS Stewart platform are distributed on the multi-dimensional singularity hypersurface in the task-space, which divides the workspace of the manipulator into several singularity-free regions. Because of the motion un- certainty at singular points, while the manipulator traverses this kind of hypersurface from one singularity-free region to another, its motion cannot be predetermined. In this paper, a detailed approach for the manipulator to traverse the singularity hypersurface with its non-persistent configuration is presented. First, the singular point transfer disturbance and the pose disturbance, which make the perturbed singular point transfer horizontally and vertically, respectively, are constructed. Through applying these disturbances into the input parameters within the maximum loss control domain, the perturbed persistent configuration is transformed into its corresponding non-persistent one. Under the action of the disturbances, the manipulator can traverse the singularity hypersurface from one singularity-flee region to another with a desired configuration. 展开更多
关键词 Parallel manipulator Singularity hypersurface Singularity-free moving region
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Two New Characterizations of H^p(D) Functions
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作者 吴丹国 章岚 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期68-71,共4页
In this paper,two new characterizations of H^p(D) functions are given.
关键词 maximal function weak L^p space
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The Maximum Temperatures (Tmax) Distribution on the Body Surface of Sport Horses
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作者 Ewa Jodkowska Krzysztof Dudek Maciej Przewozny 《Journal of Life Sciences》 2011年第4期291-297,共7页
The objective of the study was to determine the usefulness of measuring maximum temperatures in designated regions of a healthy horse's body surface. Thermographic investigations (Thermovision〉550, FLIR) were carr... The objective of the study was to determine the usefulness of measuring maximum temperatures in designated regions of a healthy horse's body surface. Thermographic investigations (Thermovision〉550, FLIR) were carried out on 35 horses from 6 to 16 years old participating in show jumping competitions. The rectal temperatures of the horses were in the range 37.5-38.2 ℃. The research was performed in a stable, the ambient temperature (Tab) of which was 14℃ with a humidity (φ) of 60%. Thermograms of the left and right side of the horses were obtained. Each thermogram consisted of 36 body surface regions (before the competition) and 25 regions (immediately after the competition). The maximum temperature ranges at rest were 21.8 ℃-31.0℃ and symmetrical regions did not differ statistically (P 〉 0.05). The highest temperatures were on the head, neck and trunk, the lowest-on the limbs. The hind legs were warmer than the front legs in analogous areas, with the exception of the gaskin and forearm. The warmest body areas had the largest surface area, which is indicative of their crucial role in the thermoregulation of the equine organism. The research results may therefore be useful in veterinary diagnosis. The range of maximum temperatures after the competitions was 25.2℃-34.2℃. The highest increment was observed at the breast, elbow, forearm and gaskin, the lowest-at the head, pastern and hoof (foreand hind limbs). Research regarding body surface temperature after exercise does not have diagnostic value for veterinarians because "warming-up" certain parts of body surface masks inflammation. 展开更多
关键词 Horses thermographic research maximum temperatures body surface.
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Designing Bézier surfaces minimizing the L^2-norm of the Gaussian curvature
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作者 MO Guo-liang WU Ming-hua 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第1期142-148,共7页
In freeform surface modelling, developable surfaces have much application value. But, in 3D space, there is not always a regular developable surface which interpolates the given boundary of an arbitrary piecewise smoo... In freeform surface modelling, developable surfaces have much application value. But, in 3D space, there is not always a regular developable surface which interpolates the given boundary of an arbitrary piecewise smooth closed curve. In this paper, tensor product Bézier surfaces interpolating the closed curves are determined and the resulting surface is a minimum of the functional defined by the L2-integral norm of the Gaussian curvature. The Gaussian curvature of the surfaces is minimized by the method of solving nonlinear optimization problems. An improved approach trust-region form method is proposed. A simple application example is also given. 展开更多
关键词 ensor product polynomial surfaces Gaussian curvature L^2-integral norm Texture mapping Nonlinear optimization
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Surface mass balance on Glacier No. 31 in the Suntar–Khayata Range, eastern Siberia, from 1951 to 2014 被引量:1
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作者 ZHANG Yong ENOMOTO Hiroyuki +3 位作者 OHATA Tetsuo KADOTA Tsutomu SHIRAKAWA Tatsuo TAKEUCHI Nozomu 《Journal of Mountain Science》 SCIE CSCD 2017年第3期501-512,共12页
This study presents a 64-year (1951-2014) reconstruction of the surface mass balance of Glacier No. 31, located in the Suntar-Khayata Range of the eastern Siberia, where the ablation zone is characterized by the ext... This study presents a 64-year (1951-2014) reconstruction of the surface mass balance of Glacier No. 31, located in the Suntar-Khayata Range of the eastern Siberia, where the ablation zone is characterized by the extensive dark ice surface. We use a temperature index-based glacier mass-balance model, which computes all major components of glacier mass budget and is forced by daily air temperature and precipitation from a nearby meteorological station. The glacier shows a mean annual mass balance of -0.35 m w.e.a-1 during the past 64 years, with an acceleration of -0.50 m w.e. a^-1 during the recent years. A cumulative mass loss of the glacier is -22.3 m w.e. over the study period, about 56% of which is observed during 1991-2014. In addition to the contribution of temperature rise and precipitation decrease to recent mass loss of the glacier, an experimental analysis, in which the clean and dark ice surfaces are respectively assumed to cover the entire ablation zone, indicates that dark ice surface, caused by insoluble impurities consisting of mineral dusts, eryoconite granules, and ice algae, plays a crucial role in the changing mass balance through enhancing melt rates in the ablation zone of the glacier. 展开更多
关键词 Mass balance Dark ice surface GlacierNo. 31 Suntar-Khayata Range Siberia
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Effect of liquid nitriding at 400–670 ℃ on microstructure and properties of C110 Steel
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作者 闫静 王均 +4 位作者 谷坛 潘东 王单奇 林元华 范洪远 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第2期325-334,共10页
Liquid nitriding of Cll0 steel was conducted in a wide range of temperatures (400-670 ℃) using a kind of chemical heat-treatments, and the hardness, mechanical and corrosion properties of the nitrided surface were ... Liquid nitriding of Cll0 steel was conducted in a wide range of temperatures (400-670 ℃) using a kind of chemical heat-treatments, and the hardness, mechanical and corrosion properties of the nitrided surface were evaluated. Experimental results revealed that the microstructure and phase constituents of the nitrided surface alloy are highly depended on the processing condition. When C 110 steel was subjected to liquid nitriding at 430 ℃, the nitrided layer was almost composed of a thin e-Fe2-3N layer. When C 110 steel was subjected to liquid nitriding at 640 ℃, the phase composition of the nitrided layer was greatly changed. The nitrided layer depth increased significantly with increasing the treating temperature. The liquid nitriding effectively improved the surface hardness. After liquid nitriding, the absorption energy of the treated sample decreased and the tensile strength increased by Charpy V-notch (CVN) test. But the elongation of treated sample decreased. The reason is that the nitrided layer of sample is hardened and there is brittlement by diffusion of nitrogen atom. Despite of treatment temperature, the liquid nitriding can improve the corrosion. After being nitrided at 430 ℃, the nitrided layer of the C110 steel was mainly composed by e-Fe2 3N, which has excellent corrosion resistance and high microhardness, the nitrided sample has the best corrosion resistance. After nitriding temperature over 580 ℃, especially at 680 ℃, the sample's surface was covered by the thick oxide layer, which has very low hardness and corrosion resistance. So, the corrosion resistance of samples is severely compromised. 展开更多
关键词 liquid nitriding treated temperature C110 steel corrosion HARDNESS properties
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Study on Site Specific Design Earthquake Ground Motion of Nuclear Power Plants in China
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作者 Zhou Bochang Li Xiaojun Li Yaqi 《Earthquake Research in China》 2008年第4期410-415,共6页
The main technical backgrounds and requirements are introduced with regard to earthquake ground motion design parameters in several domestic and American standards,codes and guides involved in the seismic analysis and... The main technical backgrounds and requirements are introduced with regard to earthquake ground motion design parameters in several domestic and American standards,codes and guides involved in the seismic analysis and design activities of nuclear power plants in China.Based on the research results from site seismic safety evaluation of domestic nuclear power plant projects in the last years,characteristics and differences of site specific design spectra are analyzed in comparison with standard response spectra,and the suitability of standard response spectra for domestic nuclear power plant projects is discussed. 展开更多
关键词 Nuclear power plant Design earthquake ground motion Standard response spectra Site specific design spectra
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3eta Diversity of Mbuna in Lake Malawi
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作者 L.G. Kanyumba W.J. Changadeya +2 位作者 A.J.D. Ambali L.A. Kamwanja E.K.W. Kaunda 《Journal of Environmental Science and Engineering》 2011年第11期1496-1506,共11页
Molecular and field studies suggest that Mbuna have limited migration range and are restricted by habitat discontinuities especially in areas where rocky habitats are separated by stretches of sand. This study estimat... Molecular and field studies suggest that Mbuna have limited migration range and are restricted by habitat discontinuities especially in areas where rocky habitats are separated by stretches of sand. This study estimated regional diversity of Mbuna in Lake Malawi. The estimated fl-diversity for all sites was 114.5 Mbuna suggesting that there was high level of allopatrism for the species complex. Sympatric index was low in the two regions of southern and northern lake and the observed high-end richness strongly correlated with minimum species richness. The sympatric index for the whole lake was 0.8, with non-monotypic species complexes showing declining values of sympatric index and the decline was dependent on the geographical scale of the area covered. The northern region sites had mean habitat ranking of 84.5% while the southern sites had habitat ranking of 56.7% supporting the observation that there are more rocky habitats in the northern part of the lake than in the southern. Implications of habitat ranking are discussed in terms of species abundance and richness. 展开更多
关键词 Mbuna beta diversity species richness species abundance
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Re-operation for parotid gland cancer following non-standard surgical treatment
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作者 Xiangmin Zhang Xiaolin Lan +3 位作者 Lianbin Liu Rong Li Fufu Xiao Folin Liu 《The Chinese-German Journal of Clinical Oncology》 CAS 2012年第4期192-195,共4页
Objective:The purpose of this study was to analyze the clinical disadvantages of non-standard surgical treatment for parotid gland cancer and probe the re-operative indication following non-standard surgical treatment... Objective:The purpose of this study was to analyze the clinical disadvantages of non-standard surgical treatment for parotid gland cancer and probe the re-operative indication following non-standard surgical treatment.Methods: Data of 58 cases suffered parotid gland cancer who received non-standard operation at other hospital and received re-operation in tumor hospital of Ganzhou from June 1998 to October 2010 were retrospectively reviewed.Results: In all cases,parotid gland cancer were residual in 46 cases,the facial nerve remaining rate was 81.0% (47/58),facial nerve branches injury rate was 3.5% (2/58),facial nerve partial resection rate was 8.6% (5/58) and total resection rate was 6.9% (4/58).The sensitivity of residual tumor was 83.3%,scanned by contrast-enhanced CT and the CT positive predictive value was 86.9%. Conclusion: Consideration of the higher residual tumor rate in patients who received non-standard operations,the re-operations were necessary.Contrast-enhanced CT positive predictive value was high for residual tumor and it was important for re-operation. 展开更多
关键词 parotid gland neoplasms CARCINOMA RE-OPERATION
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State-Vector Space and Canonical Coherent States in Noncommutative Plane
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作者 JING Si-Cong TAO Ling-Ping LIU Qiu-Yu RUAN Tu-Nan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2期249-254,共6页
The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously inclu... The structure of the state-vector space of identical bosons in noncommutative spaces is investigated. To maintain Bose-Einstein statistics the commutation relations of phase space variables should simultaneously include coordinate-coordinate non-commutativity and momentum-momentum non-commutativity, which leads to a kind of deformed Heisenberg-Weyl algebra. Although there is no ordinary number representation in this state-vector space, several set of orthogonal and complete state-vectors can be derived which are common eigenvectors of corresponding pairs of commuting Hermitian operators. As a simple application of this state-vector space, an explicit form of two-dimensional canonical coherent state is constructed and its properties are discussed. 展开更多
关键词 noncommutative space state-vector space coherent state
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A novel wide-range precision instrument for measuring three-dimensional surface topography
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作者 杨旭东 《Journal of Chongqing University》 CAS 2008年第1期52-57,共6页
We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacem... We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface. 展开更多
关键词 instrument circuit surface topography measurement error wide range precision instrument displacement sensor 3D platform
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Water vapor adsorption in activated carbon modified with hydrophilic organic salts
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作者 姚小龙 李立清 +1 位作者 李海龙 池东 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期478-486,共9页
Five different kinds of hydrophilic organic salts were used to modify commercial activated carbon in order to prepare hydrophilic carbon materials. Properties of the samples were analyzed by surface area analyzer and ... Five different kinds of hydrophilic organic salts were used to modify commercial activated carbon in order to prepare hydrophilic carbon materials. Properties of the samples were analyzed by surface area analyzer and SEM-EDX. The hydrophilic organic salts with different properties were introduced into activated carbon and significantly affected the properties of the samples.During adsorption experiments, the water vapor adsorption amount in modified samples increases by 0.57-17.12 times in temperature range from 303 to 323 K and at relative pressure below 0.50. Water molecules combined with surface hydrophilic groups through H-bonding exhibit good thermo stability. The effects of temperature, oxygen content and properties of the hydrophilic organic salts on water vapor adsorption were studied. It is indicated that water vapor adsorption in modified samples is mainly affected by the surface oxygen content. The carboxylate radicals in the hydrophilic organic salts greatly affect the micropore structure of the modified samples, while the metal ions in them exhibit limited influence. Different adsorption capacity of modified samples can be explained with the electronegativity of elements presented by Pauling. 展开更多
关键词 water vapor ADSORPTION activated carbon MODIFICATION hydrophilic organic salts
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Hard X-ray Photoelectron Spectroscopy Study of Electron Spectral Structure beyond the Known Signal Electron Peak
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作者 Alon Givon Eitan Tiferet +4 位作者 German R. Castro Juan Rubio-Zuazo Erez Golan Ilan Yaar ItzhakOrion 《Journal of Chemistry and Chemical Engineering》 2013年第7期601-605,共5页
HAXPES (hard X-ray photoelectron spectroscopy) is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films... HAXPES (hard X-ray photoelectron spectroscopy) is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films, buried layers and bulk electronic properties. In order to study these features, data for the electron IMFP (inelastic mean free path) at these energies is needed. To date, only calculated IMFP are available at energies above 5,000 eV and therefore experimental validation of these calculations are essential. In this paper, a new approach for using the HAXPES spectra is presented. This approach, treats the attenuated part of the electron spectrum as a whole to calculating the average electron energy loss. This average electron energy loss is the result of inelastic collisions in the material and hence, carry with it information about the electron transport poses. Carbon layers with thicknesses between 20 and 75 nanometer deposited over copper substrate were used to test this approach at the Spanish beam-line (Spline) in the ESRF (European synchrotron radiation facility). The measured results showed good agreement with the predictions of the multiple inelastic scattering theory. In addition, an algorithm for the experimental evaluation of electron IMFP, using the measured energy loss, is proposed. 展开更多
关键词 HAXPES IMFP carbon synchrotron.
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Physical Land Suitability Assessment for the Large Cardamom Amomum subulatum Roxb.Cultivation in Hills of Kathmandu Valley
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作者 Nabarath Baniya Michael Behme Saroja Baniya 《Chinese Journal of Population,Resources and Environment》 2009年第4期59-63,共5页
Nepal is one of the top three exporters of larger cardamom (Amomum subulatum Roxb.) in the world market contributing largely to the Nepalese economy. Sub-Himalayan range of hilly area of eastern Nepal is popular for... Nepal is one of the top three exporters of larger cardamom (Amomum subulatum Roxb.) in the world market contributing largely to the Nepalese economy. Sub-Himalayan range of hilly area of eastern Nepal is popular for large cardamom cultivation. Being similar phytogeographical and ecological setting, cultivation has begun in hills of Kathmandu Valley however land suitability needs to be evaluated with reference to specific need of the crop. Kathmandu is a valley with alluvial bottom and altitudinal range between 1200 and 2730m above sea level having cool to warm temperate climatic range. Varieties of aspects and slope gradient have potentiality for the large cardamom cultivation. Aim of the study was set to categorize available land area in the range of suitability for large cardamon cultivation on the basis of physical characteristics of the land and ecological need of crop. Land evaluation methodology has been designed along with site specific amendment in FAO framework (1976). Land use map in scale of 1:25 000 was used in geographic information system environment. Suitability was done through map overlaying methods. Aim of the study was set to categorize available land area in the range of suitability categories for large cardamom cultivation based on physical characteristics of the land matching with ecological need of crop. Analysis of data shows that altitudinal range at uplands of Kathmandu Valley and annual average rainfall and temperature are found to be within suitability range for Amomum subulaturn cultivation. Sandy loam soil, slightly acidic in nature with gentle sloping land of about 5-8° provides highly suitable condition. Result showed that more than one-third of total land area above 1800 m of altitude is suitable. Selectively, of the total area, 5% are north facing slope, 13% gentle slopes are highly suitable. 16% lands with north east orientation are moderately suitable. Most of the land areas which are marginaly suitabile for vegetable and cereal crops are highly suitable for large cardamom. Hills of northern boundary hills found to be suitable due to more rainfall distribution pattern compared to southern boundary hills. Therefore, land evaluation also identifies limitations and input requirements for sustainable production. 展开更多
关键词 land suitability GIS Amomum subulatum Roxb
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A Practical Approach Based on Equal Area Criteria for Stability Analysis of Weak Networks with Wind Generation Penetration
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作者 Rene Rossi Mohammad A.S. Masoum 《Journal of Energy and Power Engineering》 2012年第4期629-637,共9页
The performance of DFIG-based wind generation systems that interconnected to solid networks is well understood and prevalent in Europe and North America. However, the application of these renewable generating stations... The performance of DFIG-based wind generation systems that interconnected to solid networks is well understood and prevalent in Europe and North America. However, the application of these renewable generating stations to weak network has been examined in very limited occasions. Weak networks have a range of limitations from system capacities to CFCT restrictions which would need to be well understood prior to wind energy integration. Of particular interest would be how much wind generation could be integrated into a weak network prior to increasing voltage and frequency stability issues brought about by penetration issues. This paper introduces a simple and practical approach based on the equal area criteria to investigate the stability of weak networks. Simulation results that are presented to show the proposed approach is a viable preliminary assessment tool to determine system stability on weak networks with wind power penetration. 展开更多
关键词 Grid system weak system wind farm SWIS (south west interconnection system) CFCT (critical fault clearing time) DG (distributed generation) EAC (equal area criteria).
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商末周初青铜礼器纹饰制作技术初探 被引量:2
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作者 佘玲珠 董亚巍 +1 位作者 秦颍 张亚炜 《湖南省博物馆馆刊》 2010年第1期168-174,共7页
关于商周青铜礼器纹饰的制作技术学术界存在争议。为此,笔者进行了殷商晚期鼎、尊、圆底簋和西周早期鼎、方座簋的范铸模拟实验。模拟实验铸出的青铜礼器,其外观纹饰效果与古代出土同时期青铜礼器纹饰效果十分接近,这表明实验所采用的... 关于商周青铜礼器纹饰的制作技术学术界存在争议。为此,笔者进行了殷商晚期鼎、尊、圆底簋和西周早期鼎、方座簋的范铸模拟实验。模拟实验铸出的青铜礼器,其外观纹饰效果与古代出土同时期青铜礼器纹饰效果十分接近,这表明实验所采用的纹饰制作技术当是商末周初青铜礼器复杂纹饰制作方法的真实反映。当时青铜礼器表面纹饰,绝大多数应是直接在泥范表面手工制作的,其制作工艺简单,具体的操作也只是采用挖、压、贴、割等技术,所使用的工具亦较常见,如骨、竹、石、铜等材质类的刀、针、刮、铲等。 展开更多
关键词 青铜礼器 纹饰 纹饰制作
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Inversion of excitation source in ground vibration from urban railway traffic 被引量:5
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作者 WANG FuTong TAO XiaXin ZHENG Xin 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第4期950-959,共10页
Urban trains running on ground surface lead to evironmental ground vibrations in the vicinity of railwaylines. The complicated vibration source of the system can hardly be measured directly. The inversion methodology ... Urban trains running on ground surface lead to evironmental ground vibrations in the vicinity of railwaylines. The complicated vibration source of the system can hardly be measured directly. The inversion methodology in engineering seismology is borrowed here to study the dynamic exciting sourec, i.e., the wheel-rail unevenness. A dynamic coupled train-track-3D ground model is combined with a genetic algorithm for the inversion. The solution space of the inversion variables, the objective function and the solving genetic strategy of the inversion are determined, and a joint inversion for the wheel-rail unevenness source function and some track structure parameters is therefore designed. The wheel-rail unevenness PSD, being the source function of No. 13 Beijing urban railway, is obtained by the inversoin based on observed data in the field. The result indicates that the source function discribes the track unevenness in the range of wavelength over 1.2 m, and reflects properly wheel irregularites in the range of wavelength shorter than 1.2 m. It should be noticed that the urban rail traffic is not very fast, and this range of short wavelength is exactly corresponding to the main frequency band of environmental vibrations from the traffic. The unevenness of wavelength under 1.2 m is underestimated, and the ground vibration in the main frequency band must be underestimated consequently, if the track unevenness spectrum is taken as the source function. Rather than the track spectrum reflecting just the evenness of track, the wheel-rail spectrum expresses both the track unevenness and the irregularities of wheels, and therefore is more suitable to be the source function of urban railway traffic. It is also convinced that the exciting source inversion according to observed ground vibrations is an effective way to detect quantitatively the combined wheel-rail unevenness. 展开更多
关键词 urban railway traffic ground vibration vibration source INVERSION
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