Mode excitation theory and experiment of single-mode fiber directional coupler with strong coupling

The mode excitation theory is presented to analyze single-mode optical fiber directional couplers with transverse strong coupling, which either the weakly coupling theory or the ray theory fails to expound. By using the equivalence between the waveguides with square and circular cross sections, regarding the coupling zone of the coupler as a single waveguide, the excitation coefficients of the propagation modes in the coupling zone excited by the modes in the input waveguide have been evaluated. The theoretical coupling amount and insertion loss have been studied. Using a special monitoring technique to control the coupling length, several couplers with various coupling amounts have been made by the polishing method. The spectral characteristic of the coupling amount has been measured and compared with the theoretically inferred result. The two are found to agree with each other. The offset effect on the coupling amount has also been measured and it is different from that of the weak coupling device-the Stanford coupler.     

Prediction of total intake of dry matter and net energy in a lactation

Daily records on DM intake, net energy intake, and milk yield from 191 Holstein cows in six herds were used to study the differences in accuracy and precision among different methods of estimating total DM intake during a lactation. In using cumulative measures of intake from partial lactations to predict total intake, accuracy reached 85% at 100 d postpartum. Measurements of intake taken around midlactation gave better predictions of total intake than those taken during other periods of lactation. Methods were evaluated for estimating total feed intake during a lactation based on data collected intermittently and separated by either equal or unequal intervals throughout the lactation. The average percentage of bias across all sampling schemes was 6% or less of actual intake. Six of the seven sampling schemes using only 10 d of intake information throughout the lactation had correlations with actual intake of .97 or higher. For equally spaced methods, both accuracy and precision of estimation increased with increased frequency of sampling. For unequally spaced methods, accuracy increased with sampling frequency after 150 d in milk. Total milk production was used to predict feed intake during a lactation. Milk yield alone accounted for 37 and 33% of the variation of total intake using actual and estimated yields, respectively.     

非均匀粘弹介质中有限元地震数字模型

本文讨论了粘弹介质的地震波响应。假定介质为块状,且块中纵,横波速度及密度、品质因数横向分段线性连续变化。在此条件下,给出了粘弹波动方程制作时间剖面的数学模型,导出了相应的有限元方程并给出其计算方法(包括刚度矩阵、阻尼矩阵)。模拟某实际水平叠加剖面的仿真结果,展示了该方法的效果和水平。     

MATHEMATICAL ANALYSIS OF MUTATION OPERATOR AND ITS IMPROVED STRATEGY IN GENETIC ALGORITHMS

This paper analyzes the optimization problem of mutation probability in genetic algorithms by applying the definition of i-bit improved sub-space. Then fuzzy reasoning technique is adopted to determine the optimal mutation probability in different conditions. The superior convergence property of the new method is evaluated by applying it to two simulation examples.     

Ergonomics interventions for wafer‐handling task in semiconductor manufacturing industry

This article presents the ergonomic interventions in a semiconductor manufacturing company, with a focus on evaluating the effect of pod (wafer container) type and carrying distance on participants' maximal acceptable weight of lift (MAWL), heart rate (HR), wrist posture, and perceived exertion rating. Sixteen field operators participated in this study. The results indicate using the new pod with power grip handles produced greater MAWL than the old pod with pinch grip handles. On the other hand, the new pod also induced greater radial deviations than the old type. Recommendation for improving pod handle design is provided. Further, the increased carrying distance caused a decrease in MAWL and an increase in HR. Thus, using cart for intrabay pod transfer and minimizing manual carrying is also recommended. © 2002 Wiley Periodicals, Inc.     

Immobilization of type-I collagen and basic fibroblast growth factor (bFGF) onto poly (HEMA-co-MMA) hydrogel surface and its cytotoxicity study

Type-I collagen and bFGF were immobilized onto the surface of poly (HEMA-co-MMA) hydrogel by grafting and coating methods to improve its cytotoxicity. The multi-layered structure of the biocompatible layer was confirmed by FTIR, AFM and static water contact angles. The layers were stable in body-like environment (pH 7.4). Human skin fibroblast cells (HSFC) were seeded onto Col/bFGF-poly (HEMA-co-MMA), Col-poly (HEMA-co-MMA) and poly (HEMA-co-MMA) films for 1, 3 and 5 day. MTT assay was performed to evaluate the extraction toxicity of the materials. Results showed that the cell attachment, proliferation and differentiation on Col/bFGF-poly (HEMA-co-MMA) film were higher than those of the control group, which indicated the improvement of cell-material interaction. The extraction toxicity of the modified materials was also lower than that of the unmodified group. The protein and bFGF immobilized poly (HEMA-co-MMA) hydrogel might hold great promise to be a biocompatible material.     

EDS300电子压力继电器在液压系统中的应用

文章介绍EDS300电子压力继电器的性能。     

地产开发推动文物遗存保护利用的实践——新都龙藏寺片区城市设计

以新都龙藏寺片区城市设计为例,探索复合城市功能开发推动文物遗存保护利用的城市设计方法。     

Genetic parameters of estimated net energy efficiencies for milk production, maintenance, and body weight change in dairy cows

Net efficiencies of converting intake energy into energy for maintenance, milk production, and body weight change in a lactation were estimated for each of 79 Holstein cows by a two-stage multiple regression model. Cows were from 16 paternal half-sib families, which each had members in at least two of the six herds. Each cow was recorded for milk yield, net energy intake, and three efficiency traits. These were analyzed in a multitrait model containing the same 14 fixed subclasses of herd by season by parity and a random factor of sires for each of the five traits. Restricted maximum likelihood estimates of sire and residual (co)variance components were obtained by an expectation maximization algorithm with canonical transformations. Between milk yield and net energy intake, net energy efficiencies for milk yield, maintenance, and body weight change, the estimated phenotypic correlations were .36, -.02, .08, and -.06, while the genetic correlations were .92, .56, .02, and -.32, respectively. Both genetic and phenotypic correlations were zero between net energy efficiency of maintenance and that of milk yield and .17 between net energy efficiency of body weight change and that of milk yield. The estimated genetic correlation between net efficiency for lactation and milk yield is approximately 60% of that between gross efficiency and milk yield. With a heritability of .32 equivalent.49, net energy efficiency for milk yield may be worth consideration for genetic selection in certain dairy cattle populations.