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晶态氢氧化镍[Ni(OH)2]在碱性电解液中易发生相变,影响其电化学性能。文中采用微乳液快速冷冻共沉淀法制备Nd3+和Cu2+复合掺杂非晶态纳米Ni(OH)2粉体材料,并对其结构形貌及物理特性进行表征分析。结果表明,制备出的非晶态Ni(OH)2样品材料,微结构含有较多结晶水,物相近似球形,粒径大小在20—30nm。对样品电极材料的电化学性能测试发现,掺杂Nd3+和Cu2+的摩尔比为2∶1时,所制备的样品材料合成镍电极,并组装成MH-Ni模拟电池,在恒电流80mA/g下充电6h,40mA/g放电,终止电压为1.0V的充放电条件下,放电比容量高达348.0mA.h/g,放电中值电压为1.2723V,同时样品电极材料的氧化还原可逆性较好,电极过程的电化学阻抗较小。电化学性能优于目前MH-Ni生产应用的晶态β-Ni(OH)2电极材料。 相似文献
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采用尿素均相沉淀法制备出稀土La和Zn复合掺杂α-Ni(OH)2样品材料,同时采用XRD、EDS、IR和TG-DSC热分析技术对样品的微结构和组成进行了测试,并研究了样品作为MH-Ni电池正极活性材料的电化学性能。结果表明,稀土La和Zn复合掺杂α-Ni(OH)2材料具有较大的晶格间距,其含有更多的结构H2O分子,电极反应的电荷转移电阻较低;样品材料电极在以0.1C充放,终止电压1.0V的制度下,其放电比容量高达372.85mAh.g-1,同时放电中值电压较高并稳定于1.30V,1C下其放电比容量高达344.07mAh.g-1,充放电循环30次容量保持率为93.04%,显示出良好的较大倍率放电性能和循环可逆及结构稳定性能。 相似文献
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采用化学共沉淀法制备出Mg和Al复合掺杂α-Ni(OH)2,研究了碱土金属Mg和Al的掺入对材料结构和电化学性能的影响,同时将样品粉体合成镍电极并组装碱性MH-Ni模拟电池,测试其电化学性能。结果发现,与Al单独掺杂α-Ni(OH)2相比,样品材料具有更大的晶格层间距,内部微结构缺陷较多,无序性强,样品电极反应具有更好的可逆性和较小的电化学阻抗,样品电极在以0.1C充放,终止电压1.0V的制度下,其放电比容量达到358.60mAh·g-1,同时放电中值电压较高并稳定于1.30V。 相似文献
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氢氧化镍电极的修饰及电化学性能的研究 总被引:1,自引:0,他引:1
镍系列二次电池的正极活性物质Ni(OH)2的晶型和镍电极的制备工艺对电池的性能具有较大的影响。文章以镍-氢电池作为对象,着重研究作为电池正极的氢氧化镍电极。通过不同的方法制备电极的活性物质Ni(OH)2,以Co、Zn和稀土作为掺杂剂对电极进行修饰,并对不同掺杂方式构成的电池进行了测试。用金相显微镜来观察Ni(OH)2的外观、颗粒大小;通过恒电流放电曲线比较各电极的放电性能,并通过XRD谱图了解样品的晶型结构。电池性能测试结果表明:采用配位沉淀法制备的Ni(OH)2晶体为最佳;在添加剂方面,Zn、Co、Sm均对镍电极的电化学性能影响较大。 相似文献
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《现代化工》2017,(7)
为了考察Ni(OH)_2颗粒粒径与形貌对镍电极性能的影响,利用超声波沉淀法制备出了粒径小且分布均匀的球形氢氧化镍,研究了反应体系中超声波强度对氢氧化镍颗粒形貌的影响。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、粒度分析、循环伏安特性曲线、倍率充放电技术对制备的氢氧化镍材料进行表征与测试。结果表明,超声波强度对氢氧化镍颗粒形貌有显著影响,实验确定适宜的超声波强度在216 W左右;粒度分析显示制备的球形氢氧化镍颗粒粒度在10μm左右。XRD测试证明制备的氢氧化镍为β-Ni(OH)_2;循环伏安特性曲线和倍率充放电测试发现,该材料具有良好的循环保持率,在0.4 C充电3 h,静置3 min,1 C放电至1.2 V的测试条件下循环30次后循环保持率为89%,最大放电比容量达260 m Ah/g。 相似文献
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用化学沉淀法在活性炭(AC)表面和微孔内掺杂不同量的氢氧化镍,制备了氢氧化镍-活性炭[Ni(OH)2-AC]复合材料. 用X射线衍射(XRD)和氮气吸附等温线等对活性炭和复合材料进行表征,结果表明,所制材料为b-Ni(OH)2-AC复合材料. 对不同掺杂量的b-Ni(OH)2-AC复合材料的电化学性能进行了研究,循环伏安、恒流充放电实验表明,少量氢氧化镍掺入活性炭表面和微孔中,所得材料的比电容较活性炭有所提高,并具有良好的充放电性能;当氢氧化镍的掺入量为6%(w)时,所制备的超级电容器单电极表现出优良的电化学性能. 以活性炭电极作负极,复合材料作正极制成复合型超级电容器,循环性能测试发现,掺入6%(w)氢氧化镍的复合材料制成的Ni(OH)2-AC/AC复合型超级电容器比电容高达330.7 F/g,比活性炭(AC/AC)超级电容器比电容(245.6 F/g)提高了34.6%,且Ni(OH)2-AC/AC复合型超级电容器具有更好的循环充放电性能. 相似文献
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采用快速冷冻化学共沉淀法制备非晶态Ni(OH)2粉体,将其作为电化学活性物质复合碳纳米管合成镍电极材料,研究了其电化学性能. 结果表明,加入碳纳米管有效减少了镍电极的电荷转移电阻,增大了电极反应过程的质子扩散系数. 复合0.5%(w)碳纳米管合成的非晶态氢氧化镍电极材料在1 C充放电制度下,放电终止电压为1.0 V时,其放电比容量高达336.5 mA×h/g,放电中值电压为1.251 V,充放电循环30次,放电比容量保持率为96.74%,表现出较好的高倍率充放电性能. 相似文献
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M. S. J. Simmonds W. M. Blaney F. Delle Monache M. Marquina Mac-Quhae G. B. Marini Bettolo 《Journal of chemical ecology》1985,11(12):1593-1599
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. 相似文献
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Cheng-Le Zhao Shane Porzio Alan Smith Haiyan Ge H. T. Davis L. E. Scriven 《Journal of Coatings Technology and Research》2006,3(2):109-115
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. 相似文献
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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. 相似文献
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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. 相似文献
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中蓝晨光化工研究院有限公司《塑料工业》编辑部 《塑料工业》2009,37(3)
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. 相似文献
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中蓝晨光化工研究院《塑料工业》编辑部 《塑料工业》2007,35(3):1-25,67
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。 相似文献