基于BP人工神经网络的磨料水射流切割深度模型

在已知的磨料水射流切割混凝土实验数据的基础上,应用BP人工神经网络理论,并且借助MATLAB神经网络工具箱,建立磨料水射流切割深度模型.模型中包括的射流参数有射流压力、靶距、磨料粒径、磨料流量、磨料喷嘴直径、磨料喷嘴长度及横移速度.通过模型预测结果与实验结果的比较,表明模型具有一定的精度.     

Social Competence with Peers in Third Grade: Associations with Earlier Peer Experiences in Childcare1

The early developmental antecedents of individual differences in children's social functioning with peers in third grade were examined using longitudinal data from the large‐scale National Institute of Child Health and Human Development (NICHD) study of early child care. In a sample of 1,364 children, with family and child factors controlled, the frequency of positive and negative peer interactions in childcare between 24 and 54 months and the number of hours spent in childcare peer groups of different sizes (alone, dyad, small, medium, large) predicted third graders' peer competence at three levels of analysis: individual social skills, dyadic friendships, and peer‐group acceptance. Children who had more positive experiences with peers in childcare had better social and communicative skills with peers in third grade, were more sociable and co‐operative and less aggressive, had more close friends, and were more accepted and popular. Children with more frequent negative experiences with peers in childcare were more aggressive in third grade, had lower social and communicative skills, and reported having fewer friends. When children spent more time in small‐sized peer groups in childcare (four or fewer children at 24 months of age up to seven or fewer at 54 months), they were more sociable and co‐operative in third grade, but their teachers rated them as more aggressive, suggesting that such children may be more socially outgoing and active both positively and negatively. Like those who spent more time in small peer groups, children who spent more hours in medium‐sized groups received higher ratings for peer aggression by their third‐grade teachers. Children who spent more time with one other child in childcare or in small peer groups had fewer classroom friends in third grade as reported by the teacher but not according to maternal report or self‐report. There were no significant associations between the amount of time children spent in large childcare‐based peer groups and third‐grade peer social competence.     

超声场在细胞层次上的生物学效应及其分子机制

作为一种强物理因子,超声的生物学作用一直备受关注,随着生物学的发展,人们对超声生物学现象及其机理的理解逐渐深入。重点综述了超声场在细胞层次的生物学效应,总结了不同参数的超声波在不同介质环境中对细胞的增殖的促进和抑制作用以及对细胞结构与功能的影响,并在分子层面上尝试对超声的生物学效应得机理给予解释。结合实验结果,对超声生物学效应的可能物理机制进行了初步探讨,并对该课题的研究前景进行了展望。     

立普妥对老年充血性心力衰竭MS患者血清CRP和LDL-C的影响

目的探讨CRP水平和充血性心力衰竭（CHF）、代谢综合征（MS）程度之间的关系,以及应用立普妥对CHF代谢综合征预后的影响。方法观察120例CHF代谢综合征患者在常规应用心衰治疗药物的基础上,给予立普妥干预前后血清CRP和LDL-C的变化。另选30例无心衰MS患者为对照组。结果心衰代谢综合征患者CRP、LDL-C水平均明显高于无心衰代谢综合征患者（P〈0.05）相关分析显示CHF患者的CRP水平和心衰程度呈正相关（r=0.14,0.21,0.32,0.39,P〈0.05）。CHF患者的LDL-C水平和心衰程度亦呈正相关（r=0.21,0.33,0.46,0.50,P〈0.05）。药物干预组立普妥治疗前与治疗后比较,LDL-C水平有明显降低（P〈0.05）。常规治疗组治疗前与治疗后比较,LDL-C水平无明显变化（P〉0.05）。药物干预组患者给予立普妥干预治疗4,8周后比较CRP水平均有显著降低（P〈0.01）,且与应用时间的长短呈正相关（r=0.11,0.34,P〈0.05）;常规治疗组患者治疗前、后比较,CRP水平无明显变化（P〉0.05）。结论CRP可以作为CHF代谢综合征患者预后评估的重要指标之一。     

太阳能喷射式制冷系统能耗与经济性分析

选用大金的1P挂壁机FTXD25DV2C,对蒸气压缩式制冷循环(VCRC)和太阳能喷射式制冷循环(SERC)进行了能耗比较.能耗从火用和一次能源能效比(PEER)方面分析,SERC的(火用)效率为0.065,VCRC的火用效率可以达到0.392 1.SERC在集热器和喷射器中能源的利用率不高,(火用)损失最大.VCRC的一次能源能效比为2.60,而与此相比SERC的一次能源能效比为5.26.但是即使SERC的使用寿命是VCRC的3倍,SERC的初投资的年度化成本依然比VCRC高出三分之一.     

试论艺术创作中灵感的本质

灵感在艺术创作中占有重要地位。对灵感在艺术创作中的本质问题可以从灵感的主要特点加以分析。     

“家庭暴力”之法律概念解析

我国2001年修订的《婚姻法》虽然明确规定"禁止家庭暴力",但并未给予定义;随后《最高人民法院关于适用〈婚姻法〉若干问题解释(一)》虽对"家庭暴力"给予定义,但与国际公约等法律文件相比存在许多不足。这不仅大大削弱了反家庭暴力的力度,而且也不利于保护受害者的权利。由此可见,只有对家庭暴力的主体、客体、方式、程度和行为环境的范围进行深入分析,才能准确界定和在法律上表述家庭暴力的概念,从而为我国反家庭暴力立法提供参考。     

武汉城市圈进一步发展的深化研究

在中部崛起的大背景下,武汉城市圈面临大的发展机遇,也面对严峻的挑战.要把武汉城市圈真正建设成为促进中部地区崛起的重要战略支撑平台,实现其在中部地区的率先崛起,需要我们确定新的发展思路.实施新的推进机制,把企业推进到前台来,进一步加大城市圈联合协作与整体发展的力度.     

河南省扶持中小企业发展的政策研究

中小企业是经济发展的重要基础,加快中小企业的发展是经济体制改革的重要内容。特别是我国已经加入WTO,市场竞争将更为激烈,中小企业的保护和发展就显得更为重要,因此,有必要采取措施,扶持我省中小企业的发展,改善中小企业发展的内部和外部环境,增强其竞争能力。     

The uncovered set in spatial voting games

In a majority rule voting game, the uncovered set is the set of alternatives each of which can defeat every other alternative in the space either directly or indirectly at one remove. Research has suggested that outcomes under most reasonable agenda processes (both sincere and sophisticated) will be confined to the uncovered set. Most research on the uncovered set has been done in the context of voting games with a finite number of alternatives and relatively little is known about the properties of the uncovered set in spatial voting games.We examine the geometry of the uncovered set in spatial voting games and the geometry of two important subsets of the uncovered set, the Banks set and the Schattschneider set. In particular, we find both general upper and lower limits on the size of the uncovered set, and we give the exact bounds of the uncovered set for situations with three voters. For situations with three voters, we show that the Banks set is identical to the uncovered set.