镁钙质和镁质中间包涂料对钢液洁净度的影响

通过现场对比实验 ,研究了镁钙质和镁质中间包涂料对钢液洁净度的影响。结果表明 :( 1)两种涂料对钢液均有明显的脱氧作用 ,其脱氧率与钢液的原始全氧含量有关 ,原始氧含量越高 ,脱氧率越大 ;( 2 )对铝镇静钢而言 ,镁钙质涂料有比镁质涂料更好的脱氧效果 ,脱氧率能高出 5 %～ 15 % ;而对硅镇静钢 ,两种涂料对钢液的脱氧效果几乎没有差别 ;( 3)两种涂料对铝镇静钢和硅镇静钢均没有明显的脱硫作用。     

钢液脱氧工艺的发展状况分析

介绍了各种钢液脱氧工艺的发展过程及氢气、天然气脱氧和固体电解质脱氧等新型脱氧工艺的研究现状.采用氧化物冶金技术,控制钢中氧化物夹杂物的类型、尺寸和分布,以提高钢的焊接等性能已成为现行脱氧工艺研究热点:随着炉外精炼工艺的发展,钢包精炼中的扩散脱氧已成为生产低氧钢的一个重要途径.新型脱氧工艺中,脱氧产物不污染钢液的脱氧方法将成为未来的发展方向.     

镁砂与电熔合成铁铝尖晶石-刚玉复合材料的反应

以电熔合成铁铝尖晶石-刚玉复合材料和电熔镁砂为原料制备了铁铝尖晶石-镁铝尖晶石复合材料。检测了各烧后试样的线变化率、体积密度和显气孔率,并用XRD、SEM等研究了镁砂与电熔铁铝尖晶石-刚玉复合材料之间的反应,结果未发现有单一的镁铝尖晶石相生成,在高温下,MgO与铁铝尖晶石-刚玉之间存在互扩散,形成镁铝尖晶石和铁铝尖晶石固溶体;随着镁砂细粉加入量的提高,镁铝尖晶石向铁铝尖晶石中的固溶量加大;当电熔铁铝尖晶石-刚玉复合材料以颗粒加入时,发现在某些铁铝尖晶石颗粒周围存在环形裂纹;随着镁砂加入量的提高,试样的显气孔率下降,体积密度增大。     

二氧化钛对菱镁矿风化石制备铝尖晶石组成结构的影响

以菱镁矿风化石与工业氧化铝为原料,按照尖晶石理论化学计量比对两种物料进行配料,添加不同量二氧化钛,研究二氧化钛对制备的镁铝尖晶石的组成、结构、结晶度、晶胞常数的影响,用XRD和SEM对烧后试样的相组成和显微结构进行研究.用X'pert plus软件计算相对结晶度,并分析镁铝尖晶石相的晶胞参数.结果表明:当二氧化钛添加量...     

二氧化钛对菱镁矿风化石制备镁铝尖晶石组成结构的影响

以菱镁矿风化石与工业氧化铝为原料,按照尖晶石理论化学计量比对两种物料进行配料,添加不同量二氧化钛,研究二氧化钛对制备的镁铝尖晶石的组成、结构、结晶度、晶胞常数的影响,用XRD和SEM对烧后试样的相组成和显微结构进行研究。用X'pert plus软件计算相对结晶度,并分析镁铝尖晶石相的晶胞参数。结果表明:当二氧化钛添加量小于1.6 wt%时,结晶度随着二氧化钛加入量的增加而降低,主晶相镁铝尖晶石的晶胞参数却随之增大;当二氧化钛加入量为1.6～2.0%时,镁铝尖晶石对二氧化钛的置换固溶作用降低,镁铝尖晶石晶胞参数增加趋势有所减弱。一定量的二氧化钛有利于材料中镁铝尖晶石的生成,二氧化钛的最佳添加量为2.0%。     

TiO2对电熔合成镁铝尖晶石的影响

以轻烧氧化镁粉、工业氧化铝为原料合成电熔镁铝尖晶石材料,重点研究二氧化钛为添加剂对电熔合成镁铝尖晶石的物相组成,显微结构的影响,通过XRD,SEM分析试样的物相组成、晶胞参数和断口的微观形貌.研究发现:二氧化钛为外加剂可以增大镁铝尖晶石的晶胞参数、提高材料的体积密度进而改善材料的烧结性能,并且随着二氧化钛加入量的增加镁铝尖晶石的晶胞参数和晶胞体积呈现先增大后减小的变化规律.分析认为由于二氧化钛、钛酸镁固溶到镁铝尖晶石中促使镁铝尖晶石的晶胞参数和晶胞体积增大,而过量的钛酸镁位于晶界阻碍镁铝尖晶石的长大,导致镁铝尖晶石的晶胞参数和晶胞体积减小.在电熔法制备镁铝尖晶石时,二氧化钛的加入量不宜超过5wt%.     

TiO2加入量对固相烧结合成镁铝尖晶石致密化行为的影响

以低品位菱镁矿和工业α氧化铝微粉为主要原料固相烧结合成镁铝尖晶石,探讨TiO2添加剂对合成镁铝尖晶石致密化行为的影响.用X射线衍射(XRD),扫描电镜(SEM)及相关分析软件对烧后试样的相组成和显微结构进行研究,以揭示镁铝尖晶石烧结致密化的过程机理.研究结果表明:添加剂TiO2与形成镁铝尖晶石的置换固溶作用是促进固相合成镁铝尖晶石烧结致密化的重要机理,阳离子空位的产生以及镁铝尖晶石的晶格缺陷,高温下有利于镁铝尖晶石的晶体发育和长大,在空间位阻效应的作用下,达到排除气孔使试样致密化的目的;随着TiO2加入量的增多,镁铝尖晶石的致密化程度也逐渐升高,能够有效的改善制品的烧结性能和显微结构.     

轴承钢中氮化钛的生成与控制

研究了轴承钢中TiN夹杂物的形成和去除热力学,并在某钢厂开展了低钛轴承钢的生产试验.结果表明,TiN在凝固过程中可能析出并长大.减少TiN析出的有效方法是在轴承钢液相线温度1724 K和固相线温度1598 K范围内快速凝固和降低钢中Ti与N含量.脱钛可在转炉内或[O]≥35×10-6时的出钢脱氧前期进行.通过提高炉渣氧化铝和氧化钛活度比大于20,控制转炉下渣量≤5 kg/t钢,加入炉内的造渣材料中钛含量低于0.1%,可减少LF精炼过程中因钢中[Al]s还原渣中氧化钛导致的钢液增钛.在上述理论指导下,在某厂实现了[Ti] ≤25×10-6的低钛轴承钢的批量生产.     

镁铝尖晶石粉体制备及其在发光材料领域的研究进展

镁铝尖晶石作为一种有前途的绿色环保型无机功能材料,凭借其优良的性能和低廉的价格等特点而受到广泛关注。在总结镁铝尖晶石基本结构和特点的基础上,对镁铝尖晶石粉体的主要制备方法及其在发光材料领域的研究进展进行了综述。相比于传统固相法和燃烧法,液相法中的环保型水热合成技术在制备特殊形貌的纳米级镁铝尖晶石功能粉体方面具有优势。此外,分析了稀土、过渡元素离子掺杂镁铝尖晶石(MgAl₂O₄)发光材料的荧光性能特点,指出稀土掺杂镁铝尖晶石的上转换发光尚待深入研究,以适应其在生物医学中的应用;过渡元素离子掺杂镁铝尖晶石发光材料,则凭借其鲜艳的色彩表现有望作为一种有前途的固体激光材料。     

精炼铝炉用刚玉-镁铝尖晶石复合材料的制备与性能

用白刚玉、镁铝尖晶石、电熔镁砂和α-Al2O3微粉,在1 650 ℃烧结3h制备了刚玉-镁铝尖晶石复合材料.按照GBT29971982致密定形耐火制品气孔率和体积密度试验方法和静态坩埚法,并结合X射线衍射、扫描电镜和能谱分析研究了不同组成刚玉-镁铝尖晶石复合材料的常温物理性能、显微结构以及将其应用于精炼铝熔融炉用耐火材料时对高纯度铝的影响.结果表明:在1 650 ℃保温3 h的条件下,试样烧结致密,基质中有镁铝尖晶石生成;所制备的试样中,当α-Al2O3微粉与电熔镁砂的质量比为2∶1时,试样具有较好的室温物理性能,并且对高品质铝液的污染很小.     

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。