浅谈移动通信天线的方向图

总结了移动通信天线方向图信息解读要点,用WCDMA天线方向图进行覆盖仿真,评估不同天线对覆盖的影响,并指出在实际运用中天线选型的注意点。     

Life satisfaction and its related factors among institutionalized patients at a Hansen's disease sanatorium

We conducted a questionnaire survey on life styles and health status for 293 patients with Hansen's disease. They were admitted to the wards for disabled and physically able patients of Ohshima Seishoen, in Kagawa prefecture, in 1991. This institution is one of Japan's national leprosy sanitarians. We measured patients' life satisfaction with the Delighted-Terrible Scale. In this report, the distribution of life satisfaction and its associated factors were examined for 210(71.7%) respondents. Factors examined were length of treatment, physical health, and social aspects of life at the sanatorium. The major findings were as follows; 1. The patients aged under 60 had lower proportions of being satisfied with life than those aged 60 or older. The proportions of life satisfaction of the 40-59 age group were 17% for men and 22% for women, while for the 60 or older age groups were 33-44% for men and 41-45% for women. The proportions of life satisfaction in the 60 or older age groups were lower than those of community dwelling elderly persons. 2. We examined factors associated with life satisfaction for the respondents aged 60 or older. Dependence on activities of daily living (ADL) was associated with life satisfaction in some ADL items. Care and aid provided by the staff of the sanatorium may modify the relationship between ADL impairment and life satisfaction. For social aspects of life at the sanatorium, both having networks with family members and having resources other than family were associated with life satisfaction. Going out and positively spending their daily lives were associated with life satisfaction, too. These associations were significant for men. Similar patterns of association were observed for women, but were insignificant. This finding suggests that it is important for the health and medical care staff to pay attention to the social aspects of the life of elderly patients with Hansen's disease.     

Ice structure monitoring with an optical fiber sensing system

Ice has been used as an effective and economical material for constructions of roads and platforms in cold regions. However, the practical applications of this brittle material are limited by the fact that ice structures can suddenly crack due to low tensile strength, be crushed due to excessive compression, melt and become soften as temperature elevates. In this paper, an early warning system is proposed to monitor the strain state and damage characteristic of ice structures. Firstly, both fiber Bragg grating (FBG) and Brillouin optical time domain analysis/reflectometry (BOTDA/R) sensors were installed in an ice block and an ice beam to understand their axial and flexural behaviors under a concentrated load. Secondly, the solution for strain state and damage process of ice structures was derived analytically under test conditions. Finally, an outdoor ice road test bed was built and continuously monitored for 34 h to validate the early warning system and understand the early stage behavior of ice structures. The experimental results agreed well with their corresponding theoretical predictions. The early warning system with optical sensors is effective and practical for long-term monitoring for ice structures.     

Intravascular ultrasound findings after successful primary angioplasty for acute myocardial infarction: predictors of abrupt occlusion

OBJECTIVES: This study sought to evaluate the intravascular structure as depicted by intravascular ultrasound after successful primary angioplasty (i.e., without thrombolytic therapy) for acute myocardial infarction and to investigate the related predictors of acute coronary occlusion. BACKGROUND: The usefulness of primary angioplasty for acute myocardial infarction is still limited by early reocclusion. There are few data regarding the intravascular ultrasound findings after primary angioplasty. METHODS: Intravascular ultrasound was performed in 27 patients after successful primary angioplasty. Repeat coronary angiography was performed 15 min later, on the following day and 1 month after angioplasty. RESULTS: Abrupt occlusion occurred in 8 of 27 patients. Angiographic variables in patients with versus those without abrupt occlusion were not significantly different. Intravascular ultrasound disclosed a significantly smaller lumen area ([mean +/- SD] 2.49 +/- 0.72 vs. 5.06 +/- 1.52 mm2, p < 0.001) and a significantly greater percent plaque area (80.5 +/- 9.1% vs. 63.7 +/- 7.8%, p < 0.001) in patients with abrupt occlusion. There was no significant difference in external elastic membrane cross-sectional area. We classified the ultrasound appearance of the intravascular structure as smooth, irregular or filled. Abrupt occlusion occurred in none of 6 patients with a smooth intravascular structure, 24% of 17 patients with an irregular structure and in all 4 with a filled structure (p < 0.05). In the latter group, the lumen was filled with bright speckled or low echogenic material, although angiography revealed excellent coronary dilation in all these arteries. CONCLUSIONS: Intravascular ultrasound revealed a narrow lumen in coronary arteries showing abrupt occlusion after successful primary angioplasty, even though angiography disclosed successful dilation. Arteries with a lumen filled with bright speckled or low echogenic material frequently develop abrupt occlusion.     

Bridgman-Stockbarger法定向凝固温度场的数学模型

本文提出了描述Bridgman-Stockbarger法定向凝固温度场的数学模型。它为如何设计最佳性能的装置以及如何定量地控制和确定实验的工艺条件提供了理论依据。本模型的计算结界与实验值之间得到了很好的吻合。     

电场作用下Sn-5%Bi合金的胞晶生长

本文研究了直流电场作用下Sn-5%Bi合金的胞晶生长。实验结果表明,电场提高了胞晶生长的稳定性,改变胞晶生长形态,显著减少胞晶间距。提出了电场造成上述结果的作用机理。     

Porosity,pore size distribution and chloride permeability of shotcrete modified with nano particles at early age

Nano particles have been found to be effective in enhancing many properties of regular concretes. However, there is little information on the effect of nano particles on shotcrete. In fact, if similar positive effect of nano particles can also appear in shotcrete, they will greatly benefit the wide application of shotcrete in more and more repair and strengthening of structures in civil engineering, especially in corrosive environments. In this study, through experiments on 70 specimens, the effects of nano SiO₂, CaCO₃ and Al₂O₃ particles on the early-age porosity, pore size distribution, compressive strength and chloride permeability of shotcrete were investigated.Test results indicated that nano SiO₂ particles significantly increased the compressive strength and chloride penetration resistance; nano Al₂O₃ and CaCO₃ particles had slight enhancing effect on the compressive strength; nano CaCO₃ particles were most effective in promoting the chloride penetration resistance of shotcrete. As a conclusion, nano SiO₂ particles were recommended when both early age compressive strength and chloride penetration resistance were crucial, and nano CaCO₃ particles were recommended when only chloride penetration resistance was concerned for their high cost-effectiveness.     

PARTITION RATIO AT SOLID-LIQUID INTERFACE UNDER INFLUENCE OF TEMPERATURE GRADIENT AND EXTERNAL FORCE FIELD

The relationship between the partition ratio at a solid-liquid interface and the temperaturegradient or the external force field has been theoretically analysed.It is shown that under theinfluence of a temperature gradient or an external force field,the partition ratio at asolid-liquid interface will deviate from the equilibrium value.     

Modal Perturbation Method and its Applications in Structural Systems

A new perturbation method is developed to solve any eigenvalue equation of the form (A0+ΔA)X? = (B0+ΔB)X?Λ? based on the solution of an original system described by A0X = B0XΛ. The eigenvectors of the modified system are expanded in a subspace spanned with a small number of vibration modes of the original system. In doing so, the former eigenvalue equation of the modified system is transformed into a set of algebraic equations, which require a significantly less computational effort to solve for the eigensolutions of complex structural systems. Four numerical examples show that the developed technique gives rise to the eigensolution of high accuracy and it is an effective approach for dynamic reanalysis of the structures with numerous degrees of freedom. In comparison with the conventional small parameter perturbation, the developed technique is applicable to a wider range of problems, and only m mode shapes are used based on the Ritz expansion so that the final solution can be derived efficiently. The technique also extends laboratory model tests for complex structures with the concept of dynamic hybrid tests numerically and experimentally.