上游弯头和渐缩管对涡轮流量计测量性能的影响

对DN100涡轮流量计进行了基准实验、上游90°单弯头、90°双弯头和90°单弯头+DN150变DN100渐缩管+90°单弯头共17组实流实验.以仪表系数、平均仪表系数相对误差、线性度和不确定度作为评价指标,根据实验结果最终给出了涡轮流量计在3种安装条件下的推荐前后直管段长度,此时3种安装条件对涡轮流量计的测量影响才能忽略.     

一种新的差压式流量计标定方法

针对目前差压式流量计标定方法计算公式复杂,实流测量误差较大,为提高精度仍需实测校验的问题,经过对标定方法的研究,提出了广义流出系数的概念,根据流量和差压开方的比例关系,提出的新方法标定时无需经过流量公式计算,仅需一次实流校验即可标定流量计。该方法标定精度比传统法高出3~5倍,简化了标定方法,提高了测量精度。     

基于双锥流量计差压信号的气液两相流参数测量

设计了一种结构简单、加工工艺要求较低的双锥流量计,在此基础上提出了基于单个差压式流量计的气液两相流参数测量方法。提取双锥流量计差压波动信号的无量纲特征值,利用该参数建立气相体积含率的测量模型。通过对双锥流量计差压信号均值的分析表明,Lockhart-Martinelli常数与准气相流量比存在优良的线性关系,根据该线性关系建立了双锥流量计气液两相流流量测量模型。在气水两相流装置上开展了实验研究,结果表明,所建立的分相含率测量模型可在实验范围内对气相体积含率进行有效的测量,测量相对误差在8%以内;对气液两相流总流量和液相流量的测量误差可在5%以内。     

用蒙特卡罗方法预测液固两相体系中颗粒的超声衰减

为研究高浓度颗粒两相流中超声复散射现象并建立颗粒表征模型,从单颗粒弹性散射理论出发,采用蒙特卡罗方法预测不同粒度、浓度及超声频率下玻璃微珠/水颗粒两相体系中颗粒的超声衰减特性.在颗粒体积浓度低于1%时,蒙特卡罗方法与基于单散射理论的ECAH模型吻合较好,随颗粒体积浓度和颗粒尺寸增加,声的衰减呈非线性变化,二者差异增加.利用该方法预测颗粒半径为35和90μm的液固两相体系随浓度衰减变化的结果与文献实验值基本一致.蒙特卡罗方法可用于50%固相体积浓度范围内超声衰减计算并为超声法颗粒测量提供理论模型基础.     

多相流测量中涡轮流量计的影响因素分析

阐述了涡轮流量计的工作原理和动态特性,建立了涡轮流量计的多相流测量模型,并在多相流模拟装置中进行了实验验证,得出了流体密度是涡轮流量计在测量多相流的流量时的影响因子,并且讨论了流体密度影响多相流的流量测量的规律。     

多相流测量中涡轮流量计的影响因子研究

阐述了涡轮流量计的工作原理和动态特性,建立了涡轮流量计的多相流测量模型,并在多相流模拟装置中进行了实验验证,得出了流体密度是涡轮流量计在测量多相流的流量时的影响因子,并且讨论了流体密度影响多相流的流量测量的规律.     

多相流测量中涡轮流量计的影响因子分析

阐述了涡轮流量计的工作原理和动态特性,建立了涡轮流量计的多相流测量模型,并在多相流模拟装置中进行了实验验证,得出了流体密度是涡轮流量计在测量多相流的流量时的影响因子,并且讨论了流体密度影响多相流的流量测量的规律。     

涡街流量计测量气液混相流的不确定度

涡街流量计可用于部分混相流的测量,但迄今为止有关混相流对涡街流量计测量特性的影响还缺少理论研究和实践经验.在体积含气率为2.0%～15.0%的范围内,评定了用涡街流量计测量气液混相流的不确定度,提出涡街流量计测量气液混相流的不确定度计算式.实验以空气和水为介质产生气液混相流,涡街信号通过管壁差压法采集,涡街频率通过功率谱分析获得.结果表明在保持涡街流量计一定测量准确度的前提下,涡街流量计相对扩展不确定度随气液混相流流量及其体积含气率的分布比较均匀;在涡街频率测量的不确定度分量中,由重复性和复现性引起的相对标准不确定度随流量的变化呈现出较强的随机性,而由频率分辨率引起的相对标准不确定度则随着流量的增加而减小.在本研究的流量与体积含气率范围内,由气液混相流引起的涡街流量计附加相对不确定度小于2.0%.这一研究为分析气液混相流对涡街流量计测量特性的影响提供了有益的借鉴.     

气体超声流量计的分析与应用

<正>随着科学技术的发展和天然气流量测量技术研究的深入,近年来超声流量计在天然气贸易计量中得到了广泛的应用。我国于2001年内编制了GB/T 18604《用气体超声波流量计测量天然气流量》的国家标准。该类型教其它流量计有自身有点,因此近些年来除中石油西气东输管线应用超声流     

环状流液滴夹带率测量方法及分析

针对气液两相环状流液膜参数溯源问题,设计了一种液膜在线提取装置和基于液膜质量流量测量的夹带率测量方法。该装置利用超声波测距传感器对储液箱液位进行实时监测并反馈至控制系统,利用单片机控制抽气泵开关实现对环状流多孔渗水介质管段内外差压调节控制液膜析出速率,使用换向器实现计量和废液管路切换并记录两次切换之间的时间间隔。利用精密电子天平对取出液膜进行称重测量,结合记录时间和液相质量流量计测量结果实现液膜质量流量和液滴夹带率等参数的测量。在小口径高精度气液两相流模拟装置进行了75组实流验证实验,并结合两种典型夹带率模型预测结果对测量系统进行了科学评价。研究结果表明,液膜质量流量和液滴夹带率测量结果可溯源,测量准确度高,为研究气液两相环状流液膜流动特性提供了一种可靠的实验测试方法。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.