低温自燃烧法合成La2NiO4阴极材料及其性能

以柠檬酸-硝酸盐溶液为前驱体,采用低温自燃烧法合成了具有K2NiF4结构的中温固体氧化物燃料电池La2NiO4阴极材料.研究了影响溶胶和凝胶的形成以及La2NiO4粉体晶相结构的影响因素,确定了最佳的合成条件.研究结果表明:自燃烧产物经1000 ℃煅烧2 h后,形成了平均粒径约为90 nm的单一La2NiO4相.经1300 ℃烧结的La2NiO4在100～800 ℃范围内平均热膨胀系数为13.9×10-6 K-1,在600～800 ℃范围内测得的总电导率为84.5～96.3 S·cm-1.     

中温固体氧化物燃料电池YBaCo2O5+δ阴极材料的改性研究

为了提高中温固体氧化物燃料电池层状钙钛矿氧化物YBaCo2O5+δ(YBC)阴极材料的电化学性,通过掺杂和包覆对其进行了改性研究.采用乙二胺四乙酸-柠檬酸络合法合成了YBC和YBa0.5Sr0.5Co2O5+δ(YBSC)氧化物粉体;采用溶液浸渍法制备了La2NiO4+δ(LN)包覆YBSC的复合阴极La2NiO4+δ...     

固相反应合成NiO-ZnO纳米复合光催化剂

以ZnSO4·7H2O、NiSO4·6H2O和(NH4)2C2O4·H2O为原料,通过球磨固相反应首先合成出前驱物NiC2O4.2H2O-ZnC2O4·2H2O。进而将该前驱物加热分解制得p-n结型NiO-ZnO纳米复合光催化剂。用X射线衍射分析对产物的物相组成、平均晶粒大小进行表征。结果表明,在400～800℃热处理温度内,产物NiO-ZnO由立方相NiO和六角相ZnO组成;500℃煅烧2 h的NiO-ZnO样品中NiO和ZnO的平均粒径分别约为31.7 nm和17.6 nm。以Cr6+溶液和甲基橙溶液的光催化降解为模型反应,研究NiO-ZnO纳米复合光催化剂的光催化活性,实验结果表明,p-n结型NiO-ZnO纳米复合光催化剂对Cr6+的光催化还原活性高于商业P-25 TiO2和纯ZnO,但对甲基橙氧化活性却稍低于商业P-25 TiO2。     

La2O2SO4∶Eu3+的制备与发光性能研究

以La2O3、Eu2 O3和H2SO4为原料,NH3·H2O为沉淀剂,采用共沉淀法合成了La2O2SO4∶Eu3+荧光粉.结果表明pH值对前驱体及其煅烧产物的物相组成有很大影响,适合的pH值为10.该pH值合成的前驱体La2(OH)4SO4·2H2O在空气气氛下400℃煅烧2h能转化为团絮状的单相La2 O2 SO4粉体.在280 nm的紫外光激发下,La2O2SO4∶Eu3+荧光粉呈现红光发射,主发射峰位于620 nm,归属于Eu3离子的5 D0→7 F2跃迁,Eu3+离子的淬灭浓度为10mol％,并且随着煅烧温度的升高,该荧光粉的发光强度增加.     

基于片状前驱体组装中孔NiO微球

利用醇水混合溶剂作为反应介质,以硝酸镍(Ni(NO3)2.6H2O)为Ni源,尿素(CO(NH2)2)为沉淀剂,合成一种纳米片组装的碱式镍化合物微球,经热处理得到由NiO中孔纳米片组装的微球.采用X射线衍射仪、环境扫描电镜、傅立叶红外光谱仪和比表面及孔径分布测试仪对产物进行表征.结果表明:所得前驱体是一种片状结构的碱式碳酸镍盐(NiO2.45C0.74N0.25H2.90),经热处理后NiO纳米片单元上形成2.5和40 nm 2种孔径的中孔结构.改变尿素用量由0.01 mol增加至0.03 mol,会形成Ni(HCO3)2颗粒,从而改变微球表面形貌.结合PEG的模板作用和层状碱式金属盐类物质的成核及生长特性,提出了微米尺度球形组装NiO中孔纳米片的可能生长机理.     

离子交换法可控合成四钛酸钾衍生物

利用四钛酸钾(K2Ti4O9)离子交换平衡热力学模型预测了获得K2Ti4O9纯相衍生物的最优条件,并以K2Ti4O9晶须为前驱体,以目标产物的固相Ti与K摩尔比为控制目标,通过调节离子交换过程中溶液平衡pH值和用K+选择性电极控制液相K+浓度,成功合成出纯相的水合四钛酸H2Ti4O9·1 2H2O、TiO2晶须、K2Ti8O17晶须、K2Ti6O13晶须,用实验验证了预测的准确性。同时实验结果表明,只要控制了离子交换中间产物的固相化学组成,就可以控制最后产物的形式,初步探索了反应过程中组成和结构的关系。     

低温燃烧合成铬酸镧纳米粉体的结构特性

用低温燃烧合成法合成了铬酸镧纳米粉体.X射线衍射和扫描电镜分析的结果表明:粉体由La1-xCaxCrO3和少量的LaCrO4,La2CrO6和有机物组成.合成过程形成的中间相LaCrO4是凝胶分解反应不完全的结果,La2CrO6的形成与阳离子未完全络合有关.燃烧后的产物呈薄膜状,厚度约80 nm;高温煅烧时薄膜状产物中的有机物挥发和LaCrO4,La2CrO6分解导致薄膜发生破碎,并形成粒径约80 nm的粉体.煅烧后粉体尺寸均匀,但部分颗粒间存在硬团聚.     

La2Ni1-xFexO4＋δ复合氧化物的合成及表征

以EDTA为配位体,采用溶胶-凝胶法合成了La2Ni1-xFexO4+δ系复合氧化物,XRD结果表明,所有样品都具有K2NiF4型结构.通过碘量法测定结果表明Ni/Fe的平均化合价和样品的非化学计量氧含量,均随x的增加而增大;当x=0.2时,非化学计量氧含量最高为0.24620通过FT-IR发现Fe的引入导致Ni-O键的振动加强,这有利于间隙氧离子的活动.交流阻抗法测定样品的离子电导率随x的增加而逐渐增大,同一样品离子电导率在低温段随温度的升高而增大,表现出小极化子占主要的电导作用.     

甘氨酸-硝酸盐法制备La2FexCu1-xO4及其氧敏性能

采用甘氨酸-硝酸盐法制备了K2NiF4结构的La2FexCu1-xO4(x=0.01-0.05)复合氧化物,制成了厚膜型氧敏元件.采用XRD、SEM等手段对烧结体的晶体结构和表面的微观形貌进行了表征和分析.并通过改变氧敏元件的烧结温度、涂膜厚度、添加高温玻璃粉含量等工艺条件来考察对其氧敏性能的影响.实验结果表明:当0≤x≤0.05时,可以形成K2NiF4结构的A2 BO4复合氧化物.膜厚为20 μm、800℃烧结、高温玻璃粉含量为5％的厚膜型La2 Fe0.005Cu0.95O4在700℃工作时的灵敏度可以达到3.6.     

类钙钛矿型陶瓷结构和性能的研究

一系列类钙钛矿 (A2 BO4 )型结构的陶瓷材料被发现 .这类材料在化学催化活性、导电性、超导性、抗铁磁性和气敏性等方面都有新特点 .本工作对类钙钛矿型材料之一La2 NiO4 陶瓷薄膜的无机盐 -溶胶 -凝胶 (ISG)法制备 ,结构和性能关系作了研究 .发现用ISG法制备的La2 NiO4 薄膜仍具有K2 NiF4 型四方结构 ,其化学计量比、晶粒和气孔大小等对气敏性有明显影响 .优选出的此种薄膜 ,在 40 0～ 80 0℃氧化气氛 ,其电阻温度系数≤ 7.2× 10 - 4/℃ ,对氧 -氢气灵敏度≥ 1.0× 10     

Many Drugs of Abuse May Be Acutely Transformed to Dopamine,Norepinephrine and Epinephrine In Vivo

It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.     

Sapindaceae,cyanolipids, and bugs

Scentless plant bugs (Heteroptera: Rhopalidae) are so named because adults of the Serinethinae have vestigial metathoracic scent glands. Serinethines are seed predators of Sapindales, especially Sapindaceae that produce toxic cyanolipids. In two serinethine species whose ranges extend into the southern United States,Jadera haematoloma andJ. sanguinolenta, sequestration of host cyanolipids as glucosides renders these gregarious, aposematic insects unpalatable to a variety of predators. The blood glucoside profile and cyanogenesis ofJadera varies depending on the cyanolipid chemistry of hosts, and adults and larvae fed golden rain tree seeds (Koelreuteria paniculata) excrete the volatile lactone, 4-methyl-2(5H)-furanone, to which they are attracted.Jadera fed balloon vine seeds (Cardiospermum spp.) do not excrete the attractive lactone. Loss of the usual heteropteran defensive glands in serinethines may have coevolved with host specificity on toxic plants, and the orientation ofJadera to a volatile excretory product could be an adaptive response to save time.Mention of a commercial product does not consititute an endorsement by the USDA.     

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.     

2008～2009年世界塑料工业进展

收集了2008年7月～2009年6月世界塑料工业的相关资料,介绍了2008～2009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、环氧树脂、不饱和聚酯树脂)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。     

ICP-MS法测定地球化学样品中As、Cr、Ge、V等18种微量痕量元素的研究

建立了测定地球化学样品中包括As、Cr、Ge、V等18种微量、痕量元素的ICP-MS方法。地化试样用HF-HNO3混酸分解后,以1 1 HNO3溶解干渣。由于制样不使用盐酸,避免了Cl对As、Cr、Ge、V的质谱干扰。用国家一级地球化学标准物质GBW 07309制备溶液优化仪器工作参数,并用于校准。方法测定限(6s)为:0.007~6.4μg/g,精密度(RSD%,n=12)为:29%~9.4%,经过国家一级地球化学标准物质的分析验证,结果与标准值吻合。方法已应用于国土资源调查的试样分析。