共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
文章根据现行的容器标准,讨论了容器试压时容器接管封堵用封头形式及厚度计算,主要包括椭圆形封头,平盖封头、盲板法兰等封头的设计选用,并探讨了带加强肋平盖封头壁厚和加强筋数量、厚度的计算方法.该方法计算的盲板安全、经济,在中石油七建公司承建的抚顺、钦州项目得到实际应用验证,达到预期效果. 相似文献
3.
NB/T 47003.1-2009未给出容器公称直径大于2 200mm时,平盖厚度和角钢加强筋规格的计算过程。为此,进行了圆形平盖加平行角钢加强筋的设计计算,为平盖角钢加强筋的规格选择提供依据。 相似文献
4.
本文建立了用控温深孔加热板,一次性聚丙烯平底离心管消解土壤汞的前处理方法。采用控温深孔加热板作为加热装置、一次性聚丙烯平底离心管作为容器,对土壤样品进行前处理消解,并利用原子荧光光度计确认聚丙烯平底离心管空白、方法检出限、精密度和正确度。实验室结果表明,采用控温深孔加热板作为加热装置、一次性聚丙烯平底离心管作为容器,成本低、检出限低、精密度高、准确度可靠,实验操作简便,能够快速、准确完成土壤样品中汞的检测。 相似文献
5.
6.
HG5—1571~1580—85《普通碳素钢及低合金钢贮罐标准系列》已由中国标准出版社出版。该标准系列包括下列几类容器的主要结构尺寸、重量及选用说明。1.HG5—1571—85 普通碳素钢及低合金钢贮罐标准系列分类与技术条件。2.HG5—1572—85 平底平盖贮罐系列。3.HG5—1573—85 平底平顶贮罐系列。4.HG5—1574—85 平底锥顶贮罐系列5.HG5—1575—85 90°无折边锥形底。平顶贮罐系列 相似文献
7.
《中氮肥》2017,(5)
在我国,带半圆管夹套容器的设计执行的标准是《钢制化工容器强度计算规定》(HG/T20582—2011)第3章"半圆管夹套容器的设计"。《钢制化工容器强度计算规定》中规定"容器圆筒和封头部分的名义厚度和有效厚度按照不带半圆管夹套时的同一容器,根据计算压力为正压或负压,按《钢制压力容器》(GB 150—1998)的相关章节确定"。经分析,当带半圆管夹套的圆筒为真空圆筒时,《钢制化工容器强度计算规定》中的上述规定是不合理的。而对于带半圆管夹套真空圆筒未被半圆管覆盖的部分,属于两端无支撑的外压圆筒,其厚度应按《压力容器》(GB 150—2011)有关章节中的"长圆筒"计算,然后再与按《钢制化工容器强度计算规定》中的有关公式确定出的半圆管覆盖部分的圆筒厚度进行比较,取厚度计算结果两者中的较大值作为带半圆管夹套真空圆筒的设计厚度。 相似文献
8.
介绍了压力容器设计中的计算厚度、设计厚度、名义厚度、有效厚度以及不包括腐蚀裕量的最小厚度之间的关系。分析了在规则设计中,卧式容器、开孔补强、外压容器(元件)这三种情况下,其计算厚度的真正涵义。选取腐蚀裕量的一般要求。以及对于设备最小厚度的一般规定。 相似文献
9.
10.
11.
12.
M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
13.
14.
Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
15.
16.
17.
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. 相似文献
18.
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. 相似文献
19.
中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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. 相似文献
20.
中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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。 相似文献