Single umbilical artery: Prenatal findings

In 450 patients with pregnancy at high risk for fetal malformation and/or intrauterine growth retardation, the umbilical cord was investigated sonographically for the presence of a single umbilical artery. A single umbilical artery was diagnosed in four fetuses between 23 and 33 weeks of gestation and suspected in two. Three cases were overlooked at sonography. All seven surviving fetuses had growth retardation at delivery and four also showed severe malformations. Whenever a single umbilical artery is found at sonography, further work-up is required to rule out associated anomalies, intrauterine growth retardation, or chromosomal abnormality.     

平顶山市郊被动式太阳房单一系统可行性分析

本文主要分析了太阳能供热单一系统的经济效益参数和偿还年限，并结合实例进行推导、计算，论证在平顶山市郊推广单一系统的可行性。     

Cytogenetic abnormalities among perinatal deaths demonstrating a single umbilical artery

The presence of a single umbilical artery is associated with fetal congenital malformations and cytogenetic abnormalities. The incidence of chromosomal abnormalities in perinatal deaths complicated by a single umbilical artery is unknown. We studied the proportion of cytogenetic abnormalities associated with a single umbilical artery among perinatal deaths undergoing autopsy. Of 1078 autopsies, 42 (3·9 per cent) were identified with a single umbilical artery. Chromosome analysis was attempted in 21 of the 42 cases (50 per cent). There were 16 successful chromosome analyses, of which three (18·75 per cent) were abnormal. All the chromosomally abnormal fetuses had major congenital malformations. These data suggest that in a perinatal death, the presence of a single umbilical artery does not clinically alter the a priori risk of cytogenetic abnormalities.     

固定化微生物技术及其在生物脱氮中的应用

介绍了几种实用固定化微生物技术，对其进行了技术比较。简述了固定化微生物技术在生物脱氮技术中的应用，并提出一种基于颗粒污泥原理的微生物固定技术应用于单级生物脱氮。     

辽河铁岭段主要支流水质污染的综合决断

采用模糊集合理论，对辽河铁岭段的四条支流，西辽河、东辽河、招苏台河和条子河分别在枯水期、丰水期、平水期做出水质污染的综合决断，由结果可看出四条河流水质污染的不同性，为治理辽河污染提供了一定的理论依据。     

基于双热阻模型的典型芯片封装热分析及评估方法

目的研究基于双热阻模型的芯片封装热分析及评估方法,并对比分析芯片封装不同建模方式对热分析结果的影响。方法采用双热阻模型建立某ECU产品的芯片封装模型,并与"集总参数法"建模法的计算结果进行对比分析与评价。根据案例中典型的实测环境(试验箱),建立等效环境模型,并进行对比分析。结果采用双热阻模型建模的器件热仿真结果更精确,且能较好地反映芯片封装的实际热分布,从而便于发现芯片散热措施的热设计缺陷。集总参数法在应用与芯片封装建模分析时,计算误差相对较大,且无法准确表现芯片的实际散热情况。另一方面,是否建立实测环境的等效模型对计算结果影响较大。结论双热阻模型能较好地适用于芯片封装简化建模,在应用于封装芯片热分析时具有更高的精确度,且参数获取难度不大,具备较大的工程应用价值。     

FENTON氧化法处理三苯基膦生产废水的试验研究

采用Fenton试剂氧化处理三苯基膦生产废水,通过正交试验和单因素试验考察了影响因素和反应最佳条件。试验结果表明：对COD去除影响因素的大小顺序为：H2O2〉FeSO4·7H2O〉pH〉反应时间;运行最佳条件为：C（H2O2）：8mL/L,p（FeSO4·7H2O）：1．5g／L,t=120min,pH值=3和分3次投加方式,COD去除率达到为75．3％。     

荧光光纤传感器测定废水中邻硝基苯酚

将２－（４－二苯基）－６－苯基苯并恶唑包埋在增塑的ＰＶＣ膜中,基于邻硝基苯酚对ＰＢＢＯ荧光的猝灭,研制了一种邻硝基苯酚荧光光纤传感器。该传感器对邻硝基苯酚的响应具有良好的可逆性和重现性,响应时间小于５０ｓ,在１．２＊１０＾－４－２．０＊１０－６ｍｏｌ／Ｌ邻硝基苯酚浓度范围内具有好的线性关系。环境水中可能存在的常见阳离子、阴离子、酚、硝基化合物对邻硝基苯酚的测定不产生干扰,将传感器用于废水中的邻硝基     

Study of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/Bamboo Pulp Fiber Composites: Effects of Nucleation Agent and Compatibilizer

In this study, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber (BPF) composites were prepared by melt compounding and injection molding. The crystallization ability, tensile strength and modulus, flexural strength and modulus, and impact strength were found substantially increased by the addition of BPF. Tensile and flexural elongations were also moderately increased at low fiber contents (<20%). BPF demonstrated not only higher strength and modulus, but also higher failure strain than the PHBV8 matrix. Boron nitride (BN) was also investigated as a nucleation agent for PHBV8 and maleic anhydride grafted PHBV8 (MA-PHBV8) as a compatibilizer for the composite system. BN was found to increase the overall properties of the neat polymer and the composites due to refined crystalline structures. MA-PHBV8 improved polymer/fiber interactions and therefore resulted in increased strength and modulus. However, the toughness of the composites was substantially reduced due to the hindrance to fiber pullout, a major energy dissipation source during the composite deformation.     

Traditional olive orchards on sloping land: Sustainability or abandonment?

Traditional olive orchards account for a large share of the area under olives in the EU, particularly in marginal areas, like those analysed in the OLIVERO project. In general, traditional olive growing can be described as a low-intensity production system, associated with old (sometimes very old) trees, grown at a low density, giving small yields and receiving low inputs of labour and materials. Though such systems are environmentally sustainable, their economic viability has become an issue, since EU policies favour more intensive and competitive systems. Orchards that have not been intensified seem to be threatened by the recent reform of the EU olive and olive oil policy, as income support has been decoupled from production. The main purpose of this paper is to identify the present constraints to traditional olive growing, and to recommend some private and public interventions to prevent its abandonment. During the OLIVERO project, traditional olive production systems were identified and described in five target areas (Trás-os-Montes-Portugal, Cordoba and Granada/Jaen-Spain, Basilicata/Salerno-Italy, and West Crete-Greece). The causes and consequences of abandonment are discussed, based on the analysis of the costs and returns, which revealed that these systems are barely economically sustainable. Their viability is only assured if reduced opportunity costs for family labour are accepted, and the olive growing is part-time. Based on these results, recommendations are made to prevent the abandonment of traditional olive growing and to preserve its environmental benefits.