Al3+掺杂对硅酸三钙结构及水化活性的影响

利用X射线衍射仪、差示扫描量热-热重分析仪、红外光谱及微量热分析等,研究了Al3+掺杂对硅酸三钙C3S结构及活性的影响.结果表明:Al3+在C3S中固溶同时取代Ca和Si,并伴随少量Ca空位的形成保持电荷平衡.当Al2O3掺量高于0.5％(质量百分数,下同)时,Al取代Si比例增加.Al2O3掺量≤0.5％时仅使C3S晶胞参数改变,当掺量达1％时,可稳定T3晶型,符合离子稳定C3S多晶态规律.Al3+在C3S中固溶形成大量非本征缺陷,显著提高C3S早期水化反应活性.     

V、Cr固溶稳定β-C2S形成过程研究

研究了V、Cr对β-C2S形成过程的影响,在生料中分别掺入质量分数0.5%、1.0%、1.5%、2.0%的V2O5、Cr2O3,煅烧至1400 ℃,利用化学分析、XRD、SEM-EDS、高温显微分析等方法,探讨V5+、Cr3+的掺杂影响机理.结果表明:V2O5、Cr2O3均易稳定β-C2S存在,当其掺量分别大于1.0%、1.5%时,对生料易烧性及熟料矿物相的形成均有不利的影响;因V5+与 Al3+离子半径相近,可取代Al3+反应稳定MeO5-4,导致液相粘度增大,而Cr3+与 Fe3+离子半径相近,其对液相作用机理相反;V5+较Cr3+更易固溶在熟料矿物相中,故Cr2O3掺杂影响规律变化相对V2O5在掺量上存在一定的滞后性.     

Cu2+、Zn2+、Cr6+、Cd2+和Pb4+离子在水泥熟料中的固溶特性研究

通过制备未掺杂重金属以及同时掺杂Cu2+、Zn2+、Cr6+、Cd2+和Pb4+五种重金属离子的水泥熟料,利用化学分析、XRD、岩相分析、电子探针等方法研究了掺杂Cu2+、Zn2+、Cr6+、Cd2+和Pb4+离子对熟料性能的影响以及重金属在熟料矿物中的分布.研究表明:重金属的掺杂可以增加液相含量、改善生料的易烧性;在煅烧后的熟料矿物中,有巨型的阿利特矿物出现,且多被溶蚀;熟料对重金属的固化具有选择性.     

高贝利特硫铝酸盐熟料矿物的活化及其混凝土性能

研究了Ba2+、P5+、Zn2+和B3+四种外掺离子对高贝利特硫铝酸盐 (HBCSA)熟料中贝利特和C4A3S　矿物的影响机制以及活化效果最佳试样的混凝土性能。利用X射线衍射（XRD）、扫描电子显微镜（SEM）和红外光谱（IR）表征了熟料矿物结构及形貌，试验表明， Ba2+、P5+和Zn2+在高温煅烧条件下，进入β-C2S和C4A3S　矿物晶格，引起晶体结构的不对称性，造成晶格畸变，从而稳定晶型、提高矿物的水硬性；B3+对C4A3S　矿物影响不显著，而对贝利特矿物有显著负面影响。综合得出：外掺离子对β-C2S的稳定及活化效果顺序为：Ba2+＞P5+＞空白＞Zn2+＞B3+, 对C4A3S　的活性提高作用次序则为：P5+＞Ba2+＞Zn2+＞空白＞B3+，对水泥强度的提高作用依次为：Ba2+＞P5+＞Zn2+＞空白＞B3+。经Ba2+活化后的强度等级为C30 的HBCSA混凝土的抗压强度、轴心抗压强度、弹性模量等力学性能以及抗硫酸侵蚀性能、抗碳化性能和干缩等耐久性能均优于PC混凝土。     

过渡金属氧化物掺杂钛酸钡取代位置及价态的研究

从BaTiO3的晶体结构出发,分析了固溶能和晶格畸变对不同价态的过渡金属离子掺杂BaTiO3时取代位置的影响。分析结果表明:Ti4+离子在BaTiO3晶体结构中具有一定的几何松散度,Cr3+、Fe3+、Co3+和Ni2+离子半径与Ti4+的接近,取代Ti位的固溶能均较小;大量实验结果表明,掺杂前后晶格常数的变化与取代Ti位的理论结果相吻合;过渡金属(Cr、Fe、Co和Ni)氧化物掺杂BaTiO3时分别以Cr3+、Fe3+、Co3+和Ni2+取代Ti位掺杂。确定某种贱金属氧化物在BaTiO3中的具体取代位置对制备抗还原的贱金属内电极的BaTiO3基MLCC有重要意义。     

Y2O2S:Yb,Ho上转换发光材料的制备及性能

利用硫熔法制备了不同浓度的Yb和Ho掺杂的Y2O2S:Yb,Ho上转换发光材料。采用X线衍射仪、扫描电镜和荧光光谱仪对粉体的相组成、形貌和上转换发光性能进行表征。结果表明:不同浓度的Yb和Ho掺杂后没有改变Y2O2S的晶体结构;颗粒形貌较为规则,多呈现多面体状,分散性较好,颗粒表面很光滑;在980nm激光激发下,Y2O2S:Yb,Ho呈现出以绿光发射为主的上转换荧光,Yb的最佳掺杂量为8%(摩尔分数),Ho的最佳掺杂量为2%(摩尔分数),Ho3+和Yb3+掺杂浓度可显著影响不同颜色发射峰的强度;对激活离子Ho3+来说,同类离子之间发生能量传递和交叉弛豫行为,导致上转换荧光强度发生猝灭;对敏化离子Yb3+来说,Yb3+吸收能量,以热的形式释放出来,产生杂质猝灭。     

碱金属掺杂对硫硅酸钙水化性能的影响机理

碱金属离子作为水泥原料中常见的杂质离子，其存在会影响熟料矿物结构与性能。采用分析纯试剂合成碱金属掺杂的硫硅酸钙单矿物，借助等温量热仪、综合热分析、扫描电镜和²⁹Si核磁共振等手段，研究了碱金属离子对硫硅酸钙水化活性及力学性能的影响。结果表明：碱金属离子在硫硅酸钙晶体结构中的固溶，能够降低晶体结晶度，形成晶体缺陷，有效提升硫硅酸钙早期水化活性，促进其早期力学性能快速发展。同时，碱金属的掺杂能够改变水化硅酸钙(C–S–H)凝胶等产物的微观形貌及结构。其中，Li₂O掺杂能够稳定絮状形态的C–S–H凝胶，而Na₂O和K₂O掺杂能够诱导C–S–H凝胶纤维状生长。经碱金属掺杂影响，C–S–H凝胶聚合度有所增加，平均硅链长增长。     

微波水热法制备离子共掺杂的YAG:Ce~(3+)荧光粉

以Mn2+、Eu3+、Gd3+为第二激活剂,采用微波均水热方法,制备稀土离子共掺杂的YAG:Ce3+荧光粉,讨论了掺杂离子对YAG:Ce3+荧光粉性能的影响,并对物相组成以及晶体结构进行了分析。结果表明,Gd3+的掺杂对荧光粉发光性能影响明显,能够提高其荧光效率,而Mn2+、Eu3+引起荧光猝灭。上述三种离子掺杂没有改变YAG晶体结构。     

Ba~(2+)离子掺杂对C_2S结构稳定性的影响

为了避免镁钙质耐火材料表面的C_2S保护层发生晶型转变导致的剥落,从而延长镁钙材料的使用寿命,以分析纯Ca(OH)_2、Si O_2、Ba CO_3为原料,在按n(Ca O):n(Si O_2)=2 1配料的纯C_2S试样中掺入不同量的Ba CO_3(其掺入量以Ba O质量分数分别为1%、2%、3%、4%、5%和6%计算),于1 450℃保温3 h烧结制备了掺杂不同量Ba~(2+)离子的C_2S试样。通过观察烧后试样的粉化程度,并利用XRD和TEM分析物相组成和晶体结构,研究了引入Ba~(2+)离子对C_2S晶体结构稳定性的影响,同时探讨了Ba~(2+)离子稳定C_2S晶体结构的机制。结果表明:未掺杂Ba~(2+)离子的试样已完全粉化,只有γ-C_2S纯相;而掺杂Ba~(2+)离子的试样烧后粉化情况均有所减轻,其中引入4%(w)Ba O的试样没有出现粉化及明显的裂纹,仍保持β-C_2S的晶体结构。其稳定机制是:在C_2S中引入适量Ba~(2+)离子后,Ba~(2+)离子取代部分Ca~(2+)离子,降低了缺陷自由能,从而稳定了β-C_2S。     

Sb3+掺杂Li0.02(Na0.53K0.48)0.98Nb0.8Ta0.2O3无铅压电陶瓷的电学性能

用传统的固相反应烧结法制备了Li0.02(Na0.53K0.48)0.98 Nb0.8Ta0.2O3-xSb2O3(LNKNT-xSb2O3)无铅压电陶瓷,研究了Sb3+掺杂对陶瓷晶体结构、显微结构及压电性能的影响.研究结果表明,Sb3+掺杂LNKNT陶瓷属于明显的“软性”掺杂,少量掺杂Sb3+能显著提高陶瓷的烧结及压电性能.当烧结温度为1100℃,掺杂量为2wt％时,LNKNT-0.02Sb陶瓷达到最好的压电性能:d33=193 pC/N,KP=49.5％,εr=779,Pr=16μC/cm2,应变达到2.3％,但机械品质因数QM从110.97降低到了85,介电损耗tanδ从1.66％增加到了2.01％.     

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。