循环冷却水总磷分析方法的探讨

通过实验建立了以高锰酸钾-磷钒钼黄法测定循环冷却水总磷的方法。该法与ZBG76002-90行业标准测定的结果无显著性差异,但该法具有操作简便、快速、易消除干扰等特点。该法标准偏差S=0.16,相对误差E=0.36%。运用于实际生产中循环冷却水总磷的测定,得到了满意的结果。     

对粒化电炉磷渣中五氧化二磷测定方法的改进

对JC/T 1088-2008中五氧化二磷的测定方法进行了改进。该法的灵敏度比JC/T 1088-2008中的方法提高了一倍多，五氧化二磷含量为3.30%~4.87%时相对标准偏差（n=6）为0.35%~0.52%，测定结果与原方法测定结果基本一致，回收率在99.67%~102.00%之间。该法相对简单快速，易于推广，尤其适合批量试样的测定     

加热灰化法在有机肥料磷和钾测定中的应用

采用加热灰化法批量处理有机肥料样品,分光光度法测定五氧化二磷,火焰光度法测定氧化钾。该方法的测定结果与浓硫酸-过氧化氢消解法相对偏差在1.56%～3.91%,加标回收率在96.1%～102.4%。与浓硫酸-过氧化氢消解处理样品对比,该方法检验效率提高,操作安全便捷,可为有机肥料中磷和钾含量的快速测定提供参考。     

ICP—AES法测定高硅钢中的硅

研究了用ICP-AES法快速测定高硅钢中的硅,确定了最佳测定条件.在此条件下测定,获得满意结果.实验结果表明,该方法简便、快速、灵敏,检出限为0.000 9 μg/mL;RSD＜0.5 %;回收率为99 %～101 %,结果令人满意.     

不同提取方法用于复混肥中钾含量测定的对比研究

分别采用超声和振荡法提取复混肥中的钾离子并测定其氧化钾含量,与沸水提取法的测定结果进行了对比,优化测定条件后进行了精密度和加标回收实验。结果显示,超声提取5 min可完全水解出复混肥中的钾离子,该方法加标回收率为99.1%～100.6%,相对标准偏差为0.31%;振荡提取10 min可完全水解出复混肥中钾离子,该方法加标回收率为98.9%～100.9%,相对标准偏差为0.34%。     

火焰原子吸收光谱法测定绿豆、黄豆中铜、锌的含量

采用火焰原子吸收法对陕西渭南产绿豆、黄豆中的Cu、Zn微量元素的含量进行了测定。结果表明,该地产的黄豆、绿豆中Cu和Zn的含量较高,该方法测定的精密度高(RSD<3%),样品的加标回收率在96%～102%,测定结果准确可靠,为当地豆资源的开发推介提供了依据。     

离子色谱法同时测定蜂蜜中的多种糖类物质

文章建立了离子色谱法分离并测定蜂蜜中糖类物质的方法,并用该法对市售蜂蜜含糖情况进行测定。结果表明总糖含量基本在70%~80%,不同种蜂蜜其所含糖种类及含量有一定差异。结果说明,该法绿色环保、分析时间短、简便快捷、实验结果稳定可靠。     

直接测汞仪测定化妆品中汞含量

目前化妆品中汞含量的测定主要以原子荧光光度法为主,较少采用直接测汞仪法对其进行测定分析。本文通过直接测汞仪法测定化妆品中的汞含量,得出该方法回收率为95. 40%～99. 50%,RSD为1. 08%～1. 41%,对化妆品中汞标准物质进行测定,测定结果与标准值无显著差异。通过与原子荧光光度法测定化妆品中汞含量比较,并对该法准确度和精密度进行探讨,结果表明,该法具有方便、快速、准确等特点,适用于化妆品中汞含量测定。     

基于量热技术的辣椒素纯度分析方法研究

建立了差示扫描量热法测定辣椒素药物纯度的方法。考察了不同升温速率和辣椒素样品质量对测定结果的影响，确定了差示扫描量热法最佳条件为：升温速率2 K·min^-1,辣椒素样品质量为1.5～3.5 mg。该法与高效液相色谱、气相色谱-质谱以及核磁共振氢谱等方法的测定结果进行了比较，结果表明：差示扫描量热法、高效液相色谱法、气相色谱/质谱法和核磁共振氢谱法测定的辣椒素质量分数分别为98.88%、98.88%、98.04%和98.97%,最大偏差为0.93%。讨论了产生偏差的原因。差示扫描量热法操作简单、结果准确，可作为测定辣椒素药物纯度的方法。     

次灵敏线火焰原子吸收分光光度法测定锌矿中高含量锌

选择Zn的次灵敏线,实现火焰原子吸收分光光度法测定锌矿中的高含量锌。方法加标回收率为97%～104%,对锌矿样品进行7次重复测定,方法精密度RSD1.00%。该法所测结果与其它分析方法测定的结果相符。     

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.     

Novel polyurethane coating technology through glycidyl carbamate chemistry

Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.     

Highly moisture-proof polysilsesquioxane coating prepared via facile sol-gel process

A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by ¹H MAS NMR. For direct comparison purposes, an SiO₂ coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N₂ absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.     

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.