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Science in China Series E: Technological Science最新文献

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Order parameters of liquid crystal on the rubbing surfaces of alignment layers 对准层摩擦表面液晶的有序参数
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9074
Li Xuan, Rina Wu, Zeng-hui Peng, Tao Yu, Li Zhang, Shengping Ruan, Uchida Tatsuo
{"title":"Order parameters of liquid crystal on the rubbing surfaces of alignment layers","authors":"Li Xuan, Rina Wu, Zeng-hui Peng, Tao Yu, Li Zhang, Shengping Ruan, Uchida Tatsuo","doi":"10.1360/02YE9074","DOIUrl":"https://doi.org/10.1360/02YE9074","url":null,"abstract":"Liquid crystal (LC) alignment is most important in LC devices. In this paper, we quantitatively analyze the LC scalar order parameters on the rubbed surface of an alignment layer. Careful measurement of dichroic infrared absorbance is performed. The result gives the evidence that the order parameter of LC just on the rubbed alignment film is only 1/3–1/2 that in the LC bulk.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125213551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Simulation of dike-break processes in the Yellow River 黄河决堤过程的模拟
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9069
Lin Liang, J. Ni, A. Borthwick, B. Rogers
{"title":"Simulation of dike-break processes in the Yellow River","authors":"Lin Liang, J. Ni, A. Borthwick, B. Rogers","doi":"10.1360/02YE9069","DOIUrl":"https://doi.org/10.1360/02YE9069","url":null,"abstract":"Although dike-break and dam-break processes have similar unsteady and discontinuous hydrodynamic characteristics, there are significant differences. In general, dam-break simulations focus on the flood discharge, whereas dike-break simulations are required to provide detailed information on the hydraulic and breach evolution processes, such as pit-scour and breach-expansion. In order to overcome the difficulties inherent in applying existing dam-break models to dike-breaks, this paper presents an integrated model that combines the shallow water, sediment transport, riverbed deformation and breach-expansion equations. A Godunov-type finite volume method is used for the flow simulation, based on a fixed quadtree grid system. The hydrodynamic aspects of the model are validated for an idealized rectangular dam break. A representative reach in the Yellow River is selected at a location where there is a significant risk of a dike-break, and full-scale topographic and hydrologic data are available. Typical dike-break processes are successfully simulated, with predicted hydraulic characteristics and terrain changes qualitatively in agreement with laboratory data. The modeling study is of practical importance for implementation of engineering countermeasures in the Yellow River, such as breach blocking and head wrapping.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127732823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 15
A method for determining the small-sample test length of carrier rocket 运载火箭小样本试验长度的确定方法
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9070
X. Duan, Zhengming Wang
{"title":"A method for determining the small-sample test length of carrier rocket","authors":"X. Duan, Zhengming Wang","doi":"10.1360/02YE9070","DOIUrl":"https://doi.org/10.1360/02YE9070","url":null,"abstract":"To satisfy the demand of test evaluation of carrier rocket, the character of aerocraft and the primary flight error should be well considered. By making full use of tracking data and ground test data, a new method is provided to expand sample size through converting the system error of guidance instruments (SEGI) of special case into standard case. In terms of the prior distribution of the SEGI coefficients, a novel model, named Bayes spline model, is developed for precision evaluation, and its performance is analyzed subsequently. For a given threshold of precision, the test length can be determined by the posterior variance with the afore-mentioned model. Finally, it is proved by theoretical analysis and simulation that this method has clear engineering background and is able to fully exploit the test resources and enables us to draw a more reasonable conclusion.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128943999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Pore structure of SWNTs with high hydrogen storage capacity 高储氢能力单壁碳纳米管的孔隙结构
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9064
Quan-hong Yang, Chang Liu, Min Liu, Yanzhen Fan, Hui‐Ming Cheng, Maozhang Wang
{"title":"Pore structure of SWNTs with high hydrogen storage capacity","authors":"Quan-hong Yang, Chang Liu, Min Liu, Yanzhen Fan, Hui‐Ming Cheng, Maozhang Wang","doi":"10.1360/02YE9064","DOIUrl":"https://doi.org/10.1360/02YE9064","url":null,"abstract":"This paper reveals, by analyses of nitrogen cryo-adsorption isotherm, the energetic and structural heterogeneity of single-walled carbon nanotubes (SWNTs) which has a high hydrogen storage capacity. It was found that SWNTs had manifold pore structures and distributed surface energy. By comparison of the pore structures and energy distributions of SWNTs before and after hydrogen adsorption, it is preliminarily indicated that hydrogen adsorption occurred in micropores and mesopores with smaller diameter, and that the pores of different diameters determined different hydrogen adsorption processes and underwent different, structure changes during hydrogen adsorption.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134339704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
A new method for analyzing the characteristics of sampled chirped fiber grating 一种分析采样啁啾光纤光栅特性的新方法
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9071
Chengcheng Sun, Chunyun Li, Xiaoning Yu
{"title":"A new method for analyzing the characteristics of sampled chirped fiber grating","authors":"Chengcheng Sun, Chunyun Li, Xiaoning Yu","doi":"10.1360/02YE9071","DOIUrl":"https://doi.org/10.1360/02YE9071","url":null,"abstract":"On the basis of the coherence theory a new method is presented to analyze the sampled chirped fiber gratings (SCFG). With this method, more results on the SCFG are obtained, including not only the characteristics of reflectivity, transmission and time delay, but also the simplified reflectivity formula, the channel’s number, wavelength spacing and channel’s bandwidth. Therefore, this method is more systematic and perfect than the usual transfer matrix method and can well guide the design of the SCFG.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132729327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
4×10 Gb/s 800 km transmission system on G.652 fiber with dispersion compensation by chirped FBG 4×10基于G.652光纤的色散啁啾光纤光栅补偿Gb/s 800公里传输系统
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9075
S. Jian, F. Yan, Tang-jun Li, Wei Jian, L. Pei, T. Ning
{"title":"4×10 Gb/s 800 km transmission system on G.652 fiber with dispersion compensation by chirped FBG","authors":"S. Jian, F. Yan, Tang-jun Li, Wei Jian, L. Pei, T. Ning","doi":"10.1360/02YE9075","DOIUrl":"https://doi.org/10.1360/02YE9075","url":null,"abstract":"In this paper, the dispersion compensation of 4×10Gb/s 800km G.652 fiber by chirped optical fiber Bragg grating (FBG) was originally implemented. The characteristics of FBG are optimized, so that the ripple coefficient of reflectivity and time delay are less than 0.9dB and 30ps, respectively. When BER is 10−10, the power penalties of transmission are 1.36 dB. 0.89 dB, 1.67 dB and 1.32 dB.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116756438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
One-dimensional tensile constitutive equation cannot be directly generalized to deal with two-dimensional bulging mechanical problems 一维拉伸本构方程不能直接推广到二维胀形力学问题
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9067
Yuquan Song, Shumei Liu
{"title":"One-dimensional tensile constitutive equation cannot be directly generalized to deal with two-dimensional bulging mechanical problems","authors":"Yuquan Song, Shumei Liu","doi":"10.1360/02YE9067","DOIUrl":"https://doi.org/10.1360/02YE9067","url":null,"abstract":"Superplastic forming has been extensively applied to manufacture parts and components with complex shapes or high-precisions. However, superplastic formation is in multi-stress state. In a long time, uniaxial tensile constitutive equation has been directly generalized to deal with multi-stress state. Whether so doing is feasible or not needs to be proved in theory. This paper first summarizes the establishing processes of superplastic tensile and bulging constitutive equation with variable m, and, using the analytical expressions of equivalent stress δ and equivalent strain rate ε of free bulge based on the fundamentals of continuum medium plastic mechanics, derives the analytical expressions of optimum loading rules for superplastic free bulge. By comparing the quantitative results on typical superplastic alloy ZnAl22, it is shown that one-dimensional tensile constitutive equations cannot be directly generalized to deal with two-dimensional bulging quantitative mechanical problems; only superplastic bulging constitutive equation based on bulging stress state can be used to treat the quantitative mechanical problems of bulge.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115278357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Analysis of solid-liquid phase change heat transfer enhancement 固液相变强化传热分析
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9065
Yin-ping Zhang, Xin Wang
{"title":"Analysis of solid-liquid phase change heat transfer enhancement","authors":"Yin-ping Zhang, Xin Wang","doi":"10.1360/02YE9065","DOIUrl":"https://doi.org/10.1360/02YE9065","url":null,"abstract":"Solid-liquid phase change processes have two important features: the process is an approximately isothermal process and the heat of fusion of phase change material tends to be much greater than its specific heat. Therefore, if any phase change material adjacent to a hot or cold surface undergoes phase change, the heat transfer rate on the surface will be noticeably enhanced. This paper presents a novel insight into the mechanisms of heat transfer enhancement induced by solid-liquid phase change based on the analogy analysis for heat conduction with an internal heat source and solid-liquid phase change heat transfer. Three degrees of surface heat transfer enhancement for different conditions are explored, and corresponding formulae are written to describe them. The factors influencing the degrees of heat transfer enhancement are clarified and their effects quantitatively analyzed. Both the novel insight and the analysis contribute to effective application of phase change heat transfer enhancement technique.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132099156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Effects of water wave motion on pollutant transport in shallow coastal water 浅海水波运动对污染物运移的影响
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9068
J. Tao, G. Han
{"title":"Effects of water wave motion on pollutant transport in shallow coastal water","authors":"J. Tao, G. Han","doi":"10.1360/02YE9068","DOIUrl":"https://doi.org/10.1360/02YE9068","url":null,"abstract":"Based on the study of the wave propagation, breaking, longshore current and the effect of wave on current structure in the near shore area with a mild bottom slope, the wave is considered to be an important dynamic factor for pollutant transportation in the coastal water. Numerical simulation shows that the pollutant will transfer along shore when the incident wave is at an angle to the shoreline. This phenomenon is very significant if the outfall is located in the surfzone. Therefore, in the design of sea outfall, to improve near shore environment, the water wave should be considered as an important hydrodynamic factor.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115277477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 7
Theoretical analysis of thermal/electric-filed poling silica glass 热/电场极化二氧化硅玻璃的理论分析
Science in China Series E: Technological Science Pub Date : 2002-12-01 DOI: 10.1360/02YE9073
Xueming Liu, Xiaoping Zheng, Yili Guo, Hanyi Zhang, Yanhe Li
{"title":"Theoretical analysis of thermal/electric-filed poling silica glass","authors":"Xueming Liu, Xiaoping Zheng, Yili Guo, Hanyi Zhang, Yanhe Li","doi":"10.1360/02YE9073","DOIUrl":"https://doi.org/10.1360/02YE9073","url":null,"abstract":"Based on the experimental results, three basic conclusions are summarized for the thermal/electric-field poling (TEFP) silica materials, with which the second-order nonlinear optical coefficient in the bulk silica glass after TEFP is calculated, and relationships between the coefficient and the applied voltage V0 in the poling process and the thickness of the nonlinear layer created from the poling are obtained. Theoretical results show that the second-order susceptibility χ(2) and the second-harmonic efficiency η in the poled bulk glass are proportional to √V0 and V02, respectively; χ(2)∼0.2−1.6 pm/V for the bulk glass after the typical TEFP; χ(2) decreases with an increase in the poling time after the TEFP silica glass approximately reaches the steady state. Theoretical results are well consistent with the experimental reports.","PeriodicalId":119807,"journal":{"name":"Science in China Series E: Technological Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128613103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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