期刊文献+
共找到5篇文章
< 1 >
每页显示 20 50 100
Effects of storm waves on rapid deposition of sediment in the Yangtze Estuary channel 被引量:2
1
作者 Xu Fumin Zhang Changkuan +1 位作者 Mao Lihua Tao Jianfeng 《Water Science and Engineering》 EI CAS 2008年第1期27-36,共10页
Recent research on short-term topographic change in the Yangtze Estuary channel under storm surge conditions is briefly summarized. The mild-slope, Boussinesq and action balance equations are compared and analyzed. Th... Recent research on short-term topographic change in the Yangtze Estuary channel under storm surge conditions is briefly summarized. The mild-slope, Boussinesq and action balance equations are compared and analyzed. The action balance equation, SWAN, was used as a wave numerical model to forecast strong storm waves in the Yangtze Estuary. The spherical coordinate system and source terms used in the equation are described in this paper. The significant wave height and the wave orbital motion velocity near the bottom of the channel during 20 m/s winds in the EES direction were simulated, and the model was calibrated with observation data of winds and waves generated by Tropical Cyclone 9912. The distribution of critical velocity for incipient motion along the bottom was computed according to the threshold velocity formula for bottom sediment. The mechanism of rapid deposition is analyzed based on the difference between the root-mean-square value of the near-bottom wave orbital motion velocity and the bottom critical tractive velocity. The results show that a large amount of bottom sediments from Hengsha Shoal and Jiuduan Shoal are lifted into the water body when 20 m/s wind is blowing in the EES direction. Some of the sediments may enter the channel with the cross-channel current, causing serious rapid deposition. Finally, the tendency of the storm to induce rapid deposition in the Yangtze Estuary channel zone is analyzed. 展开更多
关键词 Yangtze Estuary storm waves action balance equation wave orbital motion velocity near thebottom bottom critical velocity rapid deposition
下载PDF
Rugate filters prepared by rapidly alternating deposition 被引量:1
2
作者 张俊超 方明 +2 位作者 邵宇川 晋云霞 贺洪波 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第9期258-261,共4页
A methodology for the fabrication of composite (Nb205)l-x(SiO2)~ thin-film rugate filters by using pulsed direct current magnetron sputtering is presented. The two materials are mixed using rapidly alternating dep... A methodology for the fabrication of composite (Nb205)l-x(SiO2)~ thin-film rugate filters by using pulsed direct current magnetron sputtering is presented. The two materials are mixed using rapidly alternating deposition technol- ogy. The optical properties of the composite films varying with the composition of the material are studied in detail, Refractive indices between 1.50 and 2.14 can be realized in our coating system. Two designed rugate filters with a re- flection band at the wavelength of 532 nm are fabricated using an automatic deposition process. The microstructure of the rugate filter is investigated by using scanning electron microscopy. The calculated and the measured transmittance spectra axe in good agreement with each other, The causes of the slight differences between them are also analysed. 展开更多
关键词 rapidly alternating deposition rugate filter magnetron sputtering mixed oxides
原文传递
PROTOTYPE SURFACE MICRO- PRECISION IN FUSED DEPOSITION MODELING PROCESS 被引量:2
3
作者 WANG Tianming XI Juntong JIN Ye 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2007年第1期100-106,共7页
To aim at prototype parts fabricated with fused deposition modeling (FDM) process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is e... To aim at prototype parts fabricated with fused deposition modeling (FDM) process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping (RP) process, the inherent characteristics of FDM process, and some mi- cro-scratches on the surface of the extruded fiber. Based on the micro-characters of section shape of the FDM prototype, a physical model reflecting the outer shape characters is abstracted. With the physical simplified and deduced, the evaluating equations of surface roughness are acquired. According to the FDM sample parts with special design for experimental measurement, the real surface roughness values of different inclined planes are obtained. And the measuring values of surface roughness are compared with the calculation values. Furthermore, the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied. With the references of analytic conclusions, the measuring values of the experimental part surface are revised, and the revised values nearly accord with the calculation values. Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts, some concrete measures are proposed to reduce the surface roughness of FDM parts, and the applying effects are better. 展开更多
关键词 rapid prototyping Fused deposition modeling Micro-precision Surface roughness Post processing sequence
下载PDF
Design and fabrication of broadband rugate filter 被引量:1
4
作者 张俊超 方明 +2 位作者 邵宇川 晋云霞 贺洪波 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第5期335-339,共5页
The design and the deposition of a rugate filter for broadband applications are discussed.The bandwidth is extended by increasing the rugate period continuously with depth.The width and the smoothness of the reflectio... The design and the deposition of a rugate filter for broadband applications are discussed.The bandwidth is extended by increasing the rugate period continuously with depth.The width and the smoothness of the reflection band with the distribution of the periods are investigated.The improvement of the steepness of the stopband edges and the suppression of the side lobes in the transmission zone are realized by adding two apodized rugate structures with fixed periods at the external broadband rugate filter interfaces.The rapidly alternating deposition technology is used to fabricate a rugate filter sample.The measured transmission spectrum with a reflection bandwidth of approximately 505 nm is close to that of the designed broadband rugate filter except a transmittance peak in the stopband.Based on the analysis of the cross-sectional scanning electron microscopic image of the sample,it is found that the transmission peak is most likely to be caused by the instability of the deposition rate. 展开更多
关键词 rugate filter BROADBAND rapidly alternating deposition
原文传递
PREPARATION AND CHARACTERIZATION OF POLY-CRYSTALLINE SILICON THIN FILM 被引量:1
5
作者 Y.F.Hu H.Shen +1 位作者 Z.Y.Liu L.S.Wen 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第4期309-312,共4页
Poly-crystalline silicon thin film has big potential of reducing the cost of solar cells. In this paper the preparation of thin film is introduced, and then the morphology of poly-crystalline thin film, is discussed. ... Poly-crystalline silicon thin film has big potential of reducing the cost of solar cells. In this paper the preparation of thin film is introduced, and then the morphology of poly-crystalline thin film, is discussed. On the film we developed poly-crystalline silicon thin film solar cells with efficiency up to 6.05% without anti-reflection coating. 展开更多
关键词 poly-crystalline silicon thin film RTCVD (rapid thermal chem- ical vapor deposition) SSP (silicon sheet from powder)
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部