实心多孔支撑体全膜化微型固体氧化物燃料电池的制备及性能

提出一种实心多孔支撑体全膜化微型固体氧化物燃料电池(micro solid oxide fuel cell,μSOFC)设计模型.电池用氧化钇部分稳定的氧化锆[(ZrO2)0.97(Y2O3)0.03,partially stabilized zirconia,PSZ]多孔陶瓷作为支撑体,在其上制备NiO-YSZ阳极层,分别采用离心和浸渍两种成膜工艺制备YSZ电解质膜,以La0.8Sr0.2MnO3-YSZ复合材料为阴极,对组装好的单电池进行了电化学性能测试.在850℃和800℃时,离心沉积工艺制备的单电池最大输出功率密度分别为286 mW/cm2和254 mW/cm2,而浸渍涂布法制备单电池的最大输出功率密度则分别达到572 mW/cm2和388 mW/cm2.电化学阻抗谱显示;电极极化是影响电池性能的主要因素.     

阳极NiO/YSZ含量对SOFC电化学性能的影响

采用水系流延技术制备电解质,利用涂覆法分别在电解质面涂覆Ni O/YSZ阳极和LSM/YSZ阴极得到电解质支撑型单电池。采用SEM和电化学工作站等测试手段分别对半电池的结构和单电池的电性能进行表征。研究结果表明,经1500℃保温2h烧成电解质,经1250℃保温2 h烧成半电池,电解质表面致密,阳极与电解质结合性好。Ni O/YSZ=6∶4阳极的单电池以氢气+3%H2O为燃料气,空气为氧化气,在750℃运行的最大功率密度为0.20 W/cm2,极化阻抗为0.98Ω·cm2。     

多层水系流延和共烧法制备具有阳极功能层固体氧化物燃料电池

采用多层水系流延和共烧方法制备具有阳极功能层的单电池。阳极基底、阳极功能层、电解质层和阴极层分别为Ni-YSZ、Ni-ScSZ、YSZ和LSM-ScSZ。在H2/空气气氛中,分别在700、750、800℃测试具有阳极功能层的单电池,其最大功率密度分别为：0.30、0.55W/cm2和0.8W/cm2;其对应的电池欧姆电阻（R0）分别为0.39、0.30cm2和0.19cm2。电池的极化电阻则分别为1.28、0.91cm2和0.62cm2。采用相同工艺制备无阳极功能层的单电池,其在700、750、800℃的最大功率密度分别为0.21、0.31W/cm2和0.56W/cm2,对应的R0为0.41、0.39cm2和0.28cm2。电池的极化电阻为1.40、1.27cm2和0.91cm2。这说明采用的多层水系流延和共烧法制备的固体氧化物燃料电池的阳极功能层能有效减小电池的活化极化,从而提高单电池的电化学性能。     

高强度钪铝共掺杂氧化锆电解质材料制备与性能

采用柠檬酸络合法制备了(Sc2O3)0.06(Al2O3)x(ZrO2)0.94–x(x=0,0.005,0.01,0.02)系列电解质材料。通过X射线衍射、扫描电子显微镜、电化学交流阻抗谱和力学性能测试等方法对试样进行了分析,并研究了Al2O3掺杂量对电解质材料性能的影响。结果表明:Al2O3掺杂能很好的促进电解质的烧结,有效的降低晶界电阻并提高其抗弯强度。当Sc2O3和Al2O3掺杂量分别为6%和1%摩尔分数时,800℃时氧离子电导率为0.050 S/cm,室温抗弯强度达912 MPa。采用厚度为120μm该电解质片做支撑的电池在800℃最高功率密度为0.43 W/cm2,且在0.625 A/cm2恒流放电200 h后该电池性能没有衰减。     

La2/3Sr1/3MnO3(La1.4Sr1.6Mn2O7)/Ce0.8Gd0.2O2-δ复合阴极的微观结构及热膨胀性能

采用固相反应法制备La2/3Sr1/3MnO3(LSMO3)粉体,用溶胶-凝胶法分别制备La1 4Sr1 6Mn2O7(LSMO7)和Ce0.8Gd0.2O2-δ(CGO)粉体.分别将LSMO3和LSMO7粉体与CGO粉体以1∶1的质量比均匀混合,在300MPa下冷等静压成型,并在1 500℃烧结2 h,制备了LSMO3/CGO和LSMO7/CGO复合阴极材料.研究了2种复合阴极材料的微观结构和热膨胀性能.结果表明:LSMO3/CGO与LSMO7/CGO烧结体在150～1 000℃温度范围内的平均线性热膨胀系数分别为1.52×10-5/K和1.53×10-5/K,与CGO固体电解质具有相近的热膨胀性能.烧结体断面形貌分析表明:LSMO3/CGO复合阴极具有与CGO相似的断面显微结构.     

阳极支撑三层一体化结构电池的制备及性能

采用流延工艺制备了NiO-8％Y2O3/ZrO2(YSZ)阳极支撑三层一体化结构单电池,在此基础上采用浸渍工艺在多孔YSZ基体上低温制备了高活性阴极La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF).研究发现:降低电极制备温度可以得到微观形貌可控、分布均匀的纳米电极,并且避免了电极与基体间的反应:通过控制浸渍次数,制备了不同LSCF含量的电池;随着浸渍量的增加,电极的极化电阻显著下降;在800℃时,LSCF质量分数为45％的电池的功率密度高达1090 mW/cm2,同时电池稳定运行90h,表现出了很好的稳定性.     

固体氧化物燃料电池La0.9Ca0.1Fe1-xNbxO3-δ阳极的制备及性能

采用流延法制备以ScSZ为电解质的电解质支撑电池、以LSM/ScSZ为电池阴极材料,用浸渍的方法制备优化后的钙钛矿La_(0.9)Ca_(0.1)Fe_(0.9)Nb_(0.1)O_(3–δ)(LCFNb10)阳极。结果表明:Nb的加入有利于钙钛矿材料在氢气中的稳定性,且最佳掺杂量为10%(摩尔分数)时,LCFNb10电池在氢气、一氧化碳和丙烷中的放电功率在850℃分别可达526.7、452.3、328.1 m W/cm~2,表明LCFNb10是一种极具前景的SOFC电池阳极材料。     

中温固体氧化物燃料电池SmBaCo_2O_（5＋δ）–Sm_（0.2）Ce_（0.8）O_（1.9）复合阴极材料的电化学性能

采用柠檬酸–硝酸盐自蔓延燃烧法分别合成了双钙钛矿结构的SmBaCo2O5＋δ（SBCO）阴极粉体和萤石型Sm0.2Ce0.8O1.9（SDC）电解质粉体,按3：2的质量比混合上述粉体研磨后得到复合阴极。利用X射线衍射仪研究化学相容性,直流四端子法测量电导率,热膨胀仪测量热膨胀系数;构建阳极支撑型单电池（Ni-SDC｜SDC｜SBCO-SDC）并进行了性能测试,用扫描电子显微镜观察电池的断面微结构,交流阻抗谱记录界面极化。结果表明：SBCO与SDC在1 000℃无相互作用;450～800℃,复合阴极的电导率在369～234 S/cm之间;SDC的加入降低了复合阴极的热膨胀系数;单电池具有理想的微观结构,阳极｜电解质｜阴极各界面彼此接触良好,650℃时极化电阻仅为0.031.cm2;以H2为燃料气（含体积分数3%水蒸气）,空气为氧化剂,650℃时电池的开路电压为0.77 V,输出功率最大值为640 mW/cm2。预示着SBCO-SDC是中温固体氧化物燃料电池有潜力的阴极材料。     

新型复合阴极Sr_(0.95)Ti_(0.05)Co_(0.95)O_(3-δ)–Sm_(0.2)Ce_(0.8)O_(1.9)在中低温固体氧化物燃料电池中的性能

采用柠檬酸自蔓延燃烧法合成了Sr0.95Ti0.05Co0.95O3-δ(STC)阴极粉体和Sm0.2Ce0.8O1.9(SDC)电解质粉体,将STC与SDC粉体按质量比7:3混合得到复合阴极。通过X射线衍射(XRD)、直流四端子法和热膨胀仪表征了样品的化学相容性、电导率和热膨胀系数。XRD表明,STC在900℃能够得到立方纯钙钛矿结构,复合阴极STC-SDC在工作温度区间内具有很好的化学相容性;在650℃空气气氛下STC-SDC与SDC之间的界面极化阻抗仅为0.05Ω·cm2。制备了阳极支持型(Ni O-SDC│SDC│STC-SDC)单电池,在450~650℃范围内以湿润的H2(3%水蒸汽)为燃料气,空气为氧化剂测试了单电池的性能。结果表明:阳极支撑的单电池共烧1 350℃可以得到致密的电解质层和多孔的电极,而且650℃时单电池开路电压0.82V,最大输出功率为721 m W/cm2。结果预示,在以SDC为电解质的中低温固体氧化物燃料电池(IT-SOFC)中,STC-SDC是一个很有前途的复合阴极材料。     

YSZ修饰的花瓣状氧化镍粉体的制备及其电性能表征

采用均匀沉淀法制备了花瓣状NiO粉体,对该花瓣状NiO进行YSZ(Y2O3稳定的ZrO2)修饰,以提高花瓣状NiO粉体的耐高温性,进而构建纳微结构的阳极。采用离子浸渍法制备了YSZ修饰的花瓣状NiO粉体(NiO-YSZ粉体),通过热重--差热分析、X射线衍射、扫描电子显微镜、能谱仪、透射电子显微镜等分析手段对该粉体的热性能、物相、微观形貌、晶粒大小等进行了表征。分别采用商业NiO(颗粒状)粉体和自制花瓣状NiO-YSZ粉体制备了电解质支撑型单电池的阳极,该单电池的组成为NiO+8YSZ‖8YSZ‖LSM+8YSZ,并测试了其电化学性能。结果表明:采用花瓣状NiO-YSZ粉体制备的阳极单电池在操作温度为在750、800和850℃下最大功率密度分别为0.094、0.151和0.376W/cm2,且相对应的电极极化阻抗分别为2.496、1.589和0.814Ω·cm2;而采用商业NiO制备的阳极的单电池在操作温度为在750、800和850℃下的最大功率密度分别为0.024、0.072和0.149W/cm2,且相对应的电极极化阻抗分别为4.265、2.306和1.688Ω·cm2。     

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。