利用原子吸收光谱测定陶瓷原料中钙,镁方法的研究

本文试验了利用原子吸收分光光度法测定陶瓷原料中钙、镁含量的方法。在本试验中，对影响测定准确度的各种因素，干扰情况及消除方法进行了较详细的研究，并应用所建立的方法对样品进行了测定，取得了满意的结果。     

分光光度法同时测定钛铁矿中的钙和镁

研究了甲基百里香酚蓝络合剂与钙镁显色反应的条件，混合反应体系的吸收光谱，提出了一种新的同时测定钛铁矿中的钙和镁的分光光度法。该方法简便快速，将其应用于钛铁矿中的钙和镁的测定，效果良好，方法的准确度和重现性较好。测试结果令人满意。     

利用原子吸收光谱测定陶瓷原料中钙、镁方法的研究

本文试验了利用原子吸收分光光度法（AAS）测定陶瓷原料中钙、镁含量的方法。在本试验中，对影响测定准确度的各种因素、干扰情况及消除方法进行了较详细的研究，并应用所建立的方法对样品进杆了测定，取得了满意的结果。     

火焰原子吸收法测定试剂碳酸锶中钙、镁的方法探索

本文通过实验建立了用火焰原子吸收分光光度法测定试剂碳酸锶中钙镁的含量。本法的测定范围钙为0.4～5.0μg/mL,镁为0.05～0.50μg/mL，检测极限钙为0.028μg/mL，镁为0.0013μg/mL，标准偏差钙为0.00089，镁为0.00063，回收率钙为98%～106%，镁为96%～103%。     

泥页岩中可溶性钙、镁离子含量测定方法的改进

为了测定泥页岩中可溶性钙、镁离子的含量,采用了传统的钙、镁离子含量测定方法,但由于其他离子的干扰使测定终点难以观察。因此实验研究了采用CMP混合指示剂法测定钙,以K—B混合指示剂法测定镁的方法。实验结果表明改进方法对钙、镁检测的结果比传统方法准确度和精密度高。     

分光光度法快速测定硅酸盐中镁的含量

目前水泥厂硅酸盐试样中镁的测定常采用ＥＤＴＡ滴定法,即在ｐＨ＝１０时用ＥＤＴＡ滴定钙、镁的合量,在ｐＨ＞１２时用ＥＤＴＡ滴定钙离子,然后用差减法求出镁的含量。该方法准确度低,操作麻烦。利用光度法测定镁时由于钙、镁性质相似,硅酸盐试样中大量存在的钙严重...     

钝药野木瓜果肉矿质元素含量分析

目的:测定钝药野木瓜果肉中的钙、铜、镁、锰、铁等矿质元素含量,为钝药野木瓜在药品和食品领域的开发利用提供科学依据。方法:采用湿法消解钝药野木瓜果肉,并用原子吸收分光光度法测定果肉中的钠、钙、镁等矿质元素。结果:果肉中钙、镁、钠、锰、锌的含量较高,其中镁的含量最高,锂的含量最少。结论:该方法简单,精密度好,加标回收率较高,结果准确可信。     

计算分光光度法测定瓷土中钙、镁

本文对比耳定律表示形式作了改进,将浓度表示成了吸光度的函数。以酸性铬兰K为显色剂,在PH为10的NH_3—NH_4Cl的缓冲液中,以三乙醇胺掩蔽Fe~(3+),使用721型分光光度计,用计算分光光度法可同时测定瓷土中的钙、镁含量,方法简便,结果满意。     

在混合表面活性剂存在下用4,5—二溴苯基萤光酮分光光度法测定镁

测定微量镁的光度法常用的有二甲苯胺蓝口法等,近年来提出的铬天青、漂蓝6B等多元配合物光度法具有更高的灵敏度本文研究了在混合表面活性剂 CPB 和乳化剂 OP存在下,用4,5-二溴苯基萤光酮(Br-PF)分光光度法测定微量镁。在 pH11.0时,Mg(Ⅱ)一Br-PF—CPB—OP 形成深蓝色的多元配合物,最大吸收波长在610nm,ε=1.38×10~5,是目前测定镁的光度法中灵敏度最高的方法之一。配合物的颜色在10小时内稳定不变。在掩蔽剂存在下,100倍镁量的钙不干扰,有较好的选择性。     

饮用水中钙和镁的分光光度分析

采用双波长K系数分光光度法同时测定饮用水中的钙和镁.利用L9(34)正交设计考察了以甲基百里香酚蓝(MTB)作为显色剂,与水中的钙和镁显色,用双波长K系数分光光度法同时测定饮用水中钙和镁的最佳实验条件.服从比尔定律的线性范围分别为镁0.2431～2.431 μg/mL,钙0.6012～3.407μg/mL;试样加标回收率分别为镁97.23％～102.7％和钙97.38％～101.5％;检出限分别为镁0.039 μg/mL和钙0.066 μg/mL.本法操作简单,显色稳定,结果可靠,令人满意.     

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.     

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.     

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。