浸渍Ca3(PO4)2溶液对SiC窑具材料抗氧化性的影响

SiC窑具材料浸渍Ca3(PO4)2饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性和延长使用寿命.浸渍次数越多,氧化速度越小,其中浸渍4次最佳,浸渍1-4次氧化速度常数的比值=K1K2K3K4=10.30×10-78.94×10-74.17×10-72.65×10-7=3.893.371.571.     

SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合溶液对材料抗氧化性的影响

SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命。浸渍次数越多,氧化速度越小。浸渍1~4次的氧化速度常数比值为: K1混:K2混:K3混:K4混=1.44×10-7:1.16×10-7:1.02×10-7:0.87×10-7=1.66:1.33:1.17:1,浸渍混合饱和溶液的抗氧化能力比浸渍Ca3(PO4)2饱和溶液强。     

CaO-MnO2混合矿化剂对硅微粉结合的SiC窑具氧化动力学的影响

在硅微粉结合的SiC窑具中添加CaO -MnO2 混合矿化剂可显著降低SiC窑具的氧化度。实验表明用金斯特林格方程表征硅微粉结合的SiC窑具的氧化是不准确的 ,SiC试条的氧化可用经验方程来描述 ,当矿化剂添加量为 3 %时 ,测得窑具在 110 0℃下的氧化动力学方程为 :G =5 .2 3× 10 - 4τ0 .76 ,在 13 0 0℃下的氧化动力学方程为 :G =1.2 6× 10 - 2 τ0 .4 2 。     

槲皮素-锆(Ⅳ)-柠檬酸-十二烷基磺酸钠体系荧光光度法测定槲皮素的研究

在 0 .5 4 mol/L盐酸介质中 ,有十二烷基磺酸钠的存在下 ,槲皮素与锆 ( )和柠檬酸形成多元荧光配合物 ,其组成比为槲皮素∶锆 ( )∶柠檬酸 =1∶ 2∶ 2。配合物的激发与发射波长分别为432和 495 nm时 ,槲皮素浓度在 1 .0× 1 0 -6～ 1 .0× 1 0 -5mol/L范围内与荧光强度成线性关系 ,检出限为 2 .34× 1 0 -7mol/L。该法用于鸡骨草中黄酮类化合物的测定 ,结果满意     

核黄素的循环伏安法分析

介绍了在 NH3 · H2 O- NH4 Cl( PH=1 0 )缓冲溶液中的核黄素 (维生素 B2 )循环伏安图 ;核黄素在 - 0 .545V( VS.Ag Cl/Ag)产生一个阴极峰 ;在 - 0 .50 6 V产生一个阳极峰。其波高与核黄素溶液的浓度分别在 6× 1 0 - 7～ 7× 1 0 - 6mol· l- 1和 4× 1 0 - 7～ 8× 1 0 - 6mol· l- 1范围内成线性关系 ,检测限分别为 4× 1 0 - 7mol· l- 1和 2× 1 0 - 7mol· l- 1。     

Pt/H_xMoO_3电极上甲醇的催化氧化

铂电极在c(K2 PtCl6) =2 .5× 10 -3 mol/L、c(Na2 MoO4 ) =0 .0 5mol/L、c(H2 SO4 ) =0 .5mol/L的溶液中 ,电位为 +1 1～ - 0 2V(vs.SCE) ,以 2 0mV/s的速度循环扫描 10min ,可制得一种Pt/HxMoO3 电极。用循环伏安和电位阶跃方法研究了在所制备电极上甲醇的氧化。实验结果表明 ,所制备电极对甲醇的氧化有催化作用 :(1)氧化电位比在Pt/Pt电极上降低 0 12 5V ;(2 )氧化电流为Pt/Pt电极的 6倍。讨论了Pt/HxMoO3 电极对甲醇氧化的催化机理。     

催化动力学光度法测定痕量钒(Ⅴ)的研究

研究了在 p H=4及没食子酸存在下 ,微量钒 ( )催化溴酸钾氧化邻苯二胺的动力学条件 ,建立了催化动力学光度法测定痕量钒 ( )的新方法。方法的测定范围为 0～ 0 .0 2 5 μg· 2 5 m L- 1 ,检出限为 1.18× 10 - 6 g·L- 1 ,相对标准偏差为 4 .6 3% (n=10 ) ,线性回归方程为△ A=2 5 .6 6 c(μg· 2 5 m L- 1 ) - 0 .0 15 7(r=0 .9997) ,表观摩尔吸光系数ε4 6 0 nm=3.2 7× 10 7L· m ol- 1 · cm- 1 。该法灵敏度高 ,选择性好 ,直接应用于水样和食品样中痕量钒( )的测定 ,结果满意     

曼海姆法生产硫酸钾中氯化钾单耗的计算

曼海姆法生产硫酸钾的化学反应式为 :2 KCl+ H2 SO4 K2 SO4 + 2 HCl↑2× 74.6　 174.2 6　　 x 10 0 0根据方程式可算出 ,每生产 1吨 K2 SO4 所消耗 KCl为 m(KCl)= 2× 74.6× 10 0 0174.2 6=85 6.19kg,其实也就是 K2 SO4 中 K2 O含量94.2174.2 6× 10 0 =5 4.0 6%与 KCl中 K2 O含量 94.22× 74.6× 10 0 =63 .14 %之比值 5 4.0 6%63 .14 % × 10 0 0 =85 6.19kg。当然 ,生产中硫酸钾和氯化钾的氧化钾含量都没有这么高 ,若分别用 C1 和 C2 表示 ,根据硫酸钾产品标准 HG/T 3 2 791990中氧化钾含量要求为 w(K2 O)≥ 5 0 % ,氯…     

碳酸化法制取碱式碳酸锌

碱式碳酸锌传统的生产工艺是以纯碱和硫酸锌进行复分解反应制得的。反应过程中产生杂质离子 ,若处理不当 ,会影响碱式碳酸锌的品质。用二氧化碳和氧化锌制取碱式碳酸锌 ,工艺简单 ,品质稳定。1　基本原理二氧化碳与水作用生成二元弱酸碳酸CO2 + H2 O=H2 CO3碳酸在水中大部分离解为 H+和 HCO-3 离子 ,仅有少量的 CO2 -3 离子存在于水中。H2 CO3=H+ + HCO-3 　其离子溶度积 Ksp=3× 1 0 -7HCO-3 =H+ + CO2 -3 　其离子溶度积 K′sp=6× 1 0 -11即 Ksp值为 K′sp值的 5 0 0 0倍。在温度不变的情况下 ,化学反应速度与反应物浓度乘方…     

5-溴吡啶偶氮-H的合成及应用研究

报道了新试剂 5 -溴吡啶偶氮 -H的合成方法及其与 Cu2 + 显色反应的条件。实验表明 :在弱酸性溶液中 Cu2 + 与试剂形成蓝色配合物 ,K=8.0× 1 0 7,ε=2 .5× 1 0 4L· mol- 1· cm- 1。试剂选择性好 ,应用于岩石矿样中微量铜的测定 ,结果满意     

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。