分光光度法测定水中硼的对比实验及方法评价

对现行测定水中硼的两种标准分析方法《水质硼的测定姜黄素分光光度法》和《硼的测定甲亚胺-H分光光度法》进行分析实验,分别对方法的校准曲线、试剂空白、检出限、测定下限、精密度和准确度等方面进行比对分析。结果表明,甲亚胺-H分光光度法的校准曲线线性质量和精密度良好;在实际测定中,不仅测定的精密度好、准确度高,而且具有方法操作简便快捷、干扰因素少、可操作性强的特点。因此,甲亚胺-H分光光度法是水中硼测定的优选性分析方法,适合各种水体中批量样品的分析测定。     

耐火制品—陶瓷纤维制品试验方法

本文对陶瓷纤维制品的试验方法进行全面的叙述,包括试样的制备、厚度的测定、体积密度的测定、回弹性的测定、加热永久线变化的测定、导热率的测定、抗拉强度的测定和渣球含量的测定。     

提高炭黑吸碘值测定结果的准确度

炭黑吸碘值测定是一种常用的测定炭黑比表面积的方法.影响炭黑吸碘值测试结果准确度的因素很多,如称量准确性、滴定速度、溶液浓度、测定环境和指示剂等.本文讨论炭黑吸碘值测定操作过程中影响测定结果准确性的因素.     

EDTA法同时测定铋精矿中铋与铁的研究

对EDTA法同时测定铋精矿中铋和铁的测定条件、干扰及消除、沉淀回收率等作了系统试验,拟定了在大量铋存在下测定铁,并可同时测定铋的分析方法,该法适用性好,操作简便、准确度高,适用于各类铋精矿中铋和铁的测定。     

分光光度法测定水中硼的对比实验及方法评价

对现行测定水中硼的两种标准分析方法《水质硼的测定姜黄素分光光度法》和《硼的测定甲亚胺-H分光光度法》进行分析实验,分别对方法的校准曲线、试剂空白、检出限、测定下限、精密度和准确度等方面进行比对分析。结果表明,甲亚胺-H分光光度法的校准曲线线性质量和精密度良好;在实际测定中,不仅测定的精密度好、准确度高,而且具有方法操作简便快捷、干扰因素少、可操作性强的特点。因此,甲亚胺-H分光光度法是水中硼测定的优选性分析方法,适合各种水体中批量样品的分析测定。     

毛细管气相色谱法测定白酒中的甲醇、杂醇油

采用气相色谱法和国家标准比色法分别测定白酒中的甲醇、杂醇油及其它高级醇类的的含量,通过两种测定结果比较,气相色谱法测定结果的绝对差值小于比色法,用气相色谱法还同时可测定白酒中的正丙醇、仲丁醇、正丁醇、异戊醇、异丁醇及乙酸乙酯的含量。结果表明,气相色谱法虽然是一种新方法,但测定结果准确、快速,因此,毛细管气相色谱法应是测定白酒中的甲醇、杂醇油及各种高级醇类的首选方法,已应用于实际检测中。     

气相色谱法测定异丙醇及影响因素讨论

采用SP - 5 0 2气相色谱仪 ,在GDX - 1 0 4填充柱上有效地分离异丙醇、乙醇、水 ,其它成分不干扰测定。以乙醇为内标物 ,测量峰高 ,内标法定量测定异丙醇含量 (异丙醇含量范围 2 %～ 1 0 0% ) ,2min完成一次测定过程 ,测定结果准确、快速。同时 ,对测定过程中 ,色谱柱、试样组成、测定温度等影响因素对测定结果的影响进行了讨论     

肥料中水溶性二氧化硅的测定

介绍了肥料中可溶性硅测定原理、方法及测定影响因素,以及测定过程中应采取的相应措施以提高测定的准确性。     

氧化钙含量测定方法的比较与选择

用三种不同方法对氧化钙含量进行测定,通过比较三种方法测定的精密度、准确度、测定速度和操作条件等,说明了各方法的优缺点,从而得出测定氧化钙含量的最佳方法。     

甲亚胺-H光度法检测水中硼测定条件的改进性研究

对水中硼的标准分析方法甲亚胺-H分光光度法分别从方法的测定范围、校准系列溶液及被测样品的取样量、校准曲线标准点的合理化设置、分析测定的质量控制和提高测试灵敏度等方面进行改进。结果表明,经优化改进后,分析方法的检出限为0.045 mg/L,测定下限为0.18 mg/L,测定范围为0.083～3.3 mg/L。精密度和准确度的检验结果符合技术要求。改进后的方法,测定范围拓宽了2倍,降低了测定下限,提高了测定灵敏度,适合地表水以及其他水体中硼的分析测定,也适合大批量水样的快速测定。     

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。