首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
对WK-2D型微库仑仪进行调试.从进样量、进样速度、气体流量、炉温4个方面讨论操作因素对微库伦法测定样品硫含量的影响,并确定最优操作条件.在优化条件下,对加标直馏柴油样品进行精密度和回收率考察.结果表明:进样量为1.3μL,进样速度为38档,氮气流量为260 mL/min,氧气流量为150 mL/min,汽化段温度为750℃,燃烧段温度为850℃,稳定段温度为650℃操作条件下测得直馏柴油硫含量误差低,重复性好.加标回收率在99%~102%,RSD<1%.该方法简单、快速、准确,适合大批量直馏柴油样品的测定.  相似文献   

2.
建立了微库仑仪测定车用乙醇汽油中S含量的方法.测定的最佳仪器条件是:O2流量40mL·min-1、N2流量60mL·min-1,裂解炉气化端温度750℃、稳定端温度800℃,偏压140~170mV,增益为150,进样量为4-6μL.方法的精密度小于1%、相对误差绝对值低于1.5%.实验结果表明,微库仑法测试车用乙醇汽油中S含量具有重复性好、操作简单、结果准确等优点.  相似文献   

3.
孙婷婷  马波  程仲芊  崔永刚  秦波  张喜文  孙万付 《当代化工》2012,(10):1018-1020,1023
研究以气相色谱测定苯直接氧化制苯酚反应后产物分布的方法,考察并优化了色谱分析条件。结果表明最佳色谱分析条件为:汽化室温度290℃、检测器温度320℃、升温速率5.0℃/min、载气流速2.0mL/min、分流比120:1、进样量为1μL。采用外标法定量,标准样品的回收率在95%~105%,重复性最大相对标准偏差为1.62%。  相似文献   

4.
采用DB-35石英毛细管色谱柱和FID检测器,以邻苯二甲酸二丁酯为内标物,在适宜的色谱条件下对腐霉利进行定量分析。色谱条件为柱箱温度220℃;进样口温度280℃,检测器温度280℃,气体流速为载气(N2)6mL/min,燃气(H2)30mL/min,助燃气(Air)300mL/min,分流比20:1。本方法的变异系数0.316%,平均回收率99.82%,线性相关系数为0.9999。  相似文献   

5.
用原子吸收分光光度仪对测定碱性镀铜液中铅含量进行试验研究。测量条件:波长283.3mm;空气流量 3. 14 L/min;乙炔流量 1.2 L/min;灵敏度为 0.275 μg/ml/1%;相对误差 ± 2.61%。  相似文献   

6.
以固载型过渡金属Co2+离子取代的Keg舀n型磷钼酸为催化剂,分子氧为氧化剂,在管式微分反应器中进行了催化氧化环己烯合成环氧环己烷的工艺研究,结果表明,在反应温度260℃、反应压力1.7MPa、环己烯流量0.05mL/min、氧气流量9mL/min和催化剂1.5g的条件下,单程环己烯转化率和环氧环己烷的选择性分别为11.4%和75.1%,环氧环己烷单程收率可迭85.6%。  相似文献   

7.
采用微库仑滴定仪测定松节油中微量硫(≤1.0μg/mL)含量,在偏压为165mV,氮气流速为240mL/min,氧气流速为150mL/min工作条件下,该方法的标准偏差为0.023~0.060,变异系数为7.54%~10.17%,样品加标回收率大于83%,具有简便快速等特点。  相似文献   

8.
王守箐 《应用化工》2005,34(7):445-446
建立了C.C测定消心痛原料药中氯仿、乙酸、乙酸乙酯残留量的方法。采用色谱柱为PEG-20M不锈钢柱(4m×2mm),柱温采用程序升高,起始柱温50℃维持3 min,然后以10℃/min的速率升至180℃维持5 min,再以10℃/min的速率升至280℃维持10 min。FID检测器,检测器温度320℃,进样口温度320℃,氮气为载气,流速50mL/min,氢气流速30 mL/min。空气流速400 mL/min。可使三种有机溶剂完全分离,氯仿在0.0005~0.003 mg/mL的浓度范围内呈良好的线性关系(r=0.9994),回收率为100.3%(RSD<1.0%);乙酸乙酯在0.005~0.03 mg/mL的浓度范围内呈良好的线性关系(r=0.9999),回收率为100.5%,(RSD<1.0%);乙酸在0.005~0.03 mg/mL的浓度范围内呈良好的线性关系(r=0.9997),回收率为98.7%,(RSD<1.0%)。  相似文献   

9.
分别采用生物絮凝法和化学絮凝法处理300mL COD为20000mg/L、SS为4000mg/L的洗毛废水,最佳生物絮凝条件:生物絮凝剂加入量为5mL,反应温度为30℃,先以120r/min搅拌5min、再以60r/min搅拌35min,洗毛废水pH为9.0。COD去除率达92%。最佳化学絮凝条件:化学絮凝剂加入量为30mL,反应温度为40℃,先以120r/min搅拌5min、再以60r/min搅拌25min,  相似文献   

10.
超临界流体萃取三氟氯氰菊酯及甲氰菊酯残留条件研究   总被引:3,自引:0,他引:3  
杨立荣  张兴  陈安良  周一万 《农药》2005,44(1):16-18
应用超临界流体萃取技术,建立了三氟氯氰菊酯及甲氰菊酯的萃取分离及GC检测方法。在压力5000psi、温度45℃、改性剂甲醇添加量0.04ml/g、静态萃取时间20min、CO2流量25ml,收集溶剂甲醇条件下,利用ECD检测器,在柱温80℃,检测器及进样口温度260℃,升温速率80℃恒温5min,以10℃/min程序升温,260℃恒温12min,进样量1ml,载气7psi,衰减8,补偿气47ml/min下测得三氟氯氰菊酯及甲氰菊酯的萃取率分别为98.46%和99.47%;保留时间分别为24.29min、23.14min。  相似文献   

11.
12.
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.
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.
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.
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.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号