机械加压蒸汽喷射器的性能分析

针对蒸汽喷射器在一定工作蒸汽压力下存在引射极限的问题,提出了在传统蒸汽喷射器的引射蒸汽吸入段设置风机用以提高喷射器的引射推动力。通过对机械加压和传统蒸汽喷射器性能的比较,研究了截面积比、工作蒸汽压力和蒸发温度对机械加压喷射器性能的影响,同时对机械加压喷射器的经济性进行了评价。结果表明,吸入段机械加压使喷射器的引射系数和有效能利用率都得到了提高,当截面积比为9.0,蒸发温度为98℃时,与传统喷射器相比,机械加压喷射器引射系数平均增加2.3%,有效能利用率平均提高1.1%。随着截面积比、工作蒸汽压力以及蒸发温度的升高,机械加压喷射器的引射系数均有所增加。经济评价得,机械加压后喷射器系统节省的蒸汽费用是风机运行消耗电费(即产出/投入)的4.5倍。     

带热压缩串联低温多效海水淡化系统热力性能

建立了带热压缩的6效串联低温多效蒸发海水淡化系统数学模型,并利用MATLAB语言编制程序进行了求解.针对5种不同的蒸汽喷射器(TVC)位置的流程,分析了不同流程对系统热力性能的影响.同时,针对TVC位置不变的流程,分析了加热蒸汽温度的变化对系统热力性能的影响.计算结果表明:在文中的计算范围内,相比其他4种不同TVC位置...     

蒸汽喷射压缩器的变工况特性模拟与分析

采用改进热力学,建立了蒸汽喷射压缩器变工况特性数值计算模型。结合水蒸气物性程序,对热压缩海水淡化系统中的蒸汽喷射压缩器的变工况性能进行了计算,分析了工作蒸汽压力、引射压力、混合蒸汽压力的变化对引射系数的影响。计算结果表明,当压缩蒸汽的压力高于设计值时,引射系数随压缩压力的增大而减小,而当压缩低于设计值时,引射系数保持不变;提高引射蒸汽压力会引起引射系数的增大;主动蒸汽压力偏离设计值时,主动蒸汽压力的降低（低于设计值）或提高均会引起喷射器性能的降低。     

蒸汽喷射压缩器的变工况特性分析

蒸汽喷射压缩器工作特性对系统性能产生很大的影响。文中采用气体动力函数法,建立了蒸汽喷射压缩器变工况特性数值计算模型,对热压缩海水淡化系统中的蒸汽喷射压缩器的变工况性能进行了计算,分析了工作蒸汽压力、引射压力、混合蒸汽压力对喷射系数的影响。计算结果表明,当压缩蒸汽的压力低于一定值时,喷射系数保持不变;喷射压缩器特性对蒸发压力的变化最为敏感,引射压力的微小变化将导致喷射器性能的明显变化;而提高工作蒸汽压力,在一定范围内可以提高喷射器的性能,但超过一定数值后反而会引起喷射器性能的降低。与试验结果对比表明,采用该方法能够正确地预测喷射压缩器的工作性能。     

热压缩多效蒸馏海水淡化系统能量分析

低温多效海水淡化系统(LT-MED系统)是目前商业运行的海水淡化系统的主要形式之一,其中热压缩多效蒸馏系统(MED-TVC系统)由于附加设备蒸汽压缩器(TVC)结构简单、投资少、易于维护且能较大提高系统造水能力而被广泛应用.针对MED-TVC系统和MED系统进行计算模拟,利用EUD分析方法揭示MED-TVC系统的能量利用状况以及造水能力提升的原因,指出海水淡化系统性能优化的方向.同时分析了TVC与蒸发过程之间的热集成关系,确定了系统的最佳集成关系,为不同热源(工业余热)与淡化系统结合提供理论参考.     

应用于有机朗肯循环的喷射器理论与实验研究

将喷射器应用于有机朗肯循环（ORC）,构成喷射式有机朗肯循环（EORC）。EORC中喷射器引射膨胀机的出口排气,以降低膨胀机排气压力,增大膨胀机的工作压差,来提高循环的做功能力。为分析喷射器性能对EORC循环性能的影响,以经典喷射器理论为基础,选用R600为工质,在MATLAB平台,编制喷射器引射系数与引射压力的优化程序,对喷射器的最大引射系数与最小引射压力进行优化研究。结果表明,混合压力和引射系数一定时,工作流体的引射能力随工作压力的增大不断提高,能够引射更低压力的引射流体;最大引射系数和喷射效率随工作压力增大逐渐增大。并据此设计喷射器和构建EORC实验系统,初步实验表明：相比于ORC,EORC的做功能力明显提高,但系统热效率有所降低。     

多效蒸发海水淡化系统可行域时变分析与全周期操作优化

能耗过高制约了多效蒸发（MED）海水淡化技术的大规模应用,稳态操作优化虽然能够有效减少MED系统的短期蒸汽消耗速率,但污垢累积导致该系统在长周期运行时蒸汽消耗量升高和装置减产。为此,首先针对带蒸汽压缩机（TVC）的MED系统（MED-TVC）提出可行域的概念,分析表明操作点在可行域中的位置决定了系统的运行效益。随后通过可行域的时变分析发现操作点超出可行域是稳态优化中系统性能逐渐衰减的原因。最后利用可行域的性质,提出了时变约束的全周期操作优化方法。该方法通过调整MED-TVC系统在运行周期内的操作条件,获得全周期最低的蒸汽消耗量,同时利用时变的可行域约束保证优化结果在全周期内均满足淡水产量要求。结果表明,时变约束的全周期操作优化在维持MED-TVC系统的设计淡水产量的同时,全周期蒸汽消耗量相比于设计值减少了19.6%,能够很好地解决MED-TVC系统的操作优化问题。     

不同几何尺寸蒸汽喷射器的三维模拟研究

蒸汽喷射器是利用高压流体(称工作流体)抽吸低压流体(称引射流体)以提高引射流体压力的设备。采用FLUENT数值模拟来分析蒸汽喷射器内部流场变化,在其他结构条件喷嘴不变化的情况下,分别对结构参数(喷嘴直径比和渐缩段长度)对蒸汽喷射器性能的影响进行了数值模拟。研究表明:当喷嘴直径比(喷嘴出口直径与喷嘴喉部直径之比)为2时、渐缩段长度为30 mm时,喷射器的引射系数达到最大。     

研究操作参数对喷射泵工作性能的影响

以索科洛夫对喷射泵设计理论为基础,结合matlab编译语言对配套薄膜蒸发装置中的喷射泵的喷射系数进行计算,分析主要操作参数(工作蒸汽、引射蒸汽和混合蒸汽压力)对喷射泵工作性能的影响。     

多效蒸发技术浓缩石化企业含盐废水的操作方案优化分析

采用浓缩石化企业含盐废水的多效蒸发(MED)实验室小试装置,并结合热性能分析的方法,优化考察了蒸发器类型(升膜、降膜)和效数对含盐废水浓缩效果的影响。同时,基于MED运行过程中物料和热量平衡,建立了一套计算MED系统加热蒸汽利用率(HSU)的数学模型。结果表明,以汽水比(GWR)和浓缩比(CR)为评价指标,一效升膜的性能优于一效降膜;从一效至三效系统,随着效数的增加,MED系统的性能提高,三效MED系统汽水比为0.50∶1,浓缩比可达3.57。三效降-升-升的HSU最高,为80.32%,被确定为最优操作方案。     

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.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。