反铁磁性超微氧化铬的制备

用硝酸铬(或氯化铬)溶液与碳酸氢铵(碳酸铵)溶液反应生成一种组成稳定的中间物[Cr_2(NH_3)_2(CO_3)_2(OH)_2(H_2O)_2]·3Cr(OH)_3·2NH_4HCO_3·H_2O,经520℃热分解得到粒径为0.05μm的且有反铁磁性的Cr_2O_3。     

酸浸法制备硫酸铝时铝矾土矿的筛选

我国铝矾土矿属于高铝、高硅、低铁类矿,是酸浸法制备硫酸铝的良好原料。属于高铝、高硅的铝矾土矿主要有以下一些种类:蓝晶石Al_2O_3SiO_2、红栓石Al_2O_3SiO_2、硅线石Al_2O_3SiO_2、霞石(Na、K)_2OAl_2O_32SiO_2、长石(Na、K)_2OAl_2O_3·6SiO_2、白云母K_2O·Al_2O_3·6SiO_2·2H_2O、绢云母K_2O·3Al_2O_3·6SiO_2·2H_2O、白榴石K_2O·Al_2O_3·4SiO_2、高岭石Al_2O_3·SiO_2·2H_2O等。一水软铝石Al_2O_3H_2O、一水硬铝石Al_2O_3H_2O、三水铝石Al_2O_3·3H_2O等是属于高铝低硅的     

钨系杂多酸及其加合物的热分析研究

采用热重(TG)和差示扫描(DSC)热分析方法测量和研究了十二钨硅酸H_4SiW_(12)O_(40)·6H_2O、H_4SiW_(12)O_(40)·8.5H_2O及其加合物H_4SiW_(12)O_(40)·6DMF·H_2O、H_4SiW_(12)O_(40)·8DMSO·H_2O和十二钨磷酸H_3PW_(12)O_(40)·20H_2O及其加合物H_3PW_(12)O_(40)·6DMSO的热分解行为和热稳定性。     

加热速度对α-Al_2O_3·3H_2O热分解的影响

一、前言α-Al_2O_3·3H_2O(Gibbsite)是制备各种各样氧化铝的主要原料,它在热解过程中的相变化,已有许多研究。Brown等用x射线衍射及差热分析法(DTA)研究粗颗粒α-Al_2O_3·3H_2O的热分解时,首先提出了沿二条途径分解的机理,这一机理现已被普遍地接受。在粗颗粒α-Al_2O_3·3H_2O的DTA曲线上,600℃以前有三个吸热峰(脱水峰)(1、2、3、4、5、]:第一吸热峰(虽然对其成因有着不同的解释)相应于α-Al_2O_3·3H_2O部     

聚磷酸铝的研制

<正> 一、前言聚磷酸铝即三聚磷酸二氢铝(AlH_2P_3O_(10)),是一种多形态的聚磷酸盐。包括AlH_2P_3O_(10)(Ⅰ),AlH_2P_3O_(10)(Ⅱ),AlH_2P_3O_(10)·0.53H_2O,AlH_2P_3O_(10)·1.45H_2O,AlH_2P_3O_(10)·2H_2O,AlH_2P_3O_(10)·     

尿素均相沉淀法制备超细CeO2的研究

以Ce(NO_3)_3·6H_2O和尿素为原料,采用均相沉淀方法制备CeO_2前驱体经灼烧获得了超细CeO_2粉体。前驱体经灼烧分解形成CeO_2的过程中,在形貌和尺寸上具有遗传性,可通过控制反应条件来控制所制备的前驱体的形貌及大小控制所制备的粉体的形貌及大小。制备了球形,粒径在200纳米左右,尺寸均一,分散性好的CeO_2粉体。     

快速脱水对α-Al_2O_3·3H_2O热解生成过渡态氧化铝的影响

一、前言粗颗粒α-Al_2O_3·3H_2O在空气中缓慢脱水时,首先生成α-Al_2O_3·H_2O,接着生成X-Al_2O_3,然后随着温度的提高,将按照各自的相变途径,最终转变成α-Al_2O_3。如果在真空中脱水,同样先生成α-Al_2O_3·H_2O,接着生成ρ-Al_2O_3,而不是生成X-Al_2O_3,但最终产物也是α-Al_2O_3。     

CoFe_2O_4的制备及电子结构

采用尿素燃烧法,以Fe(NO_3)_3·9H_2O、Co(NO_3)2·6H_2O、CO(NH_2)_2等为原料,制备出了CoFe_2O_4多晶材料。XRD分析表明制备的CoFe_2O_4多晶体为尖晶石结构;形貌研究表明,制备的样品的晶粒生长完整,晶粒的大小较均匀,平均晶粒尺寸为0.5μm左右;Co2p、Fe2p和01s芯能级光电子谱的分析表明,制备的CoFe_2O_4铁氧体为正尖晶石和反尖晶石的混合体,并且钴铁氧体的性质与Co和Fe离子的价态分布密切相关。     

沉淀法制备α-Fe2O3纳米晶

研究了以FeCl3·6H2O和FeSO4·7H2O为源物质,用均相沉淀法和直接沉淀法制备α-Fe2O3纳米晶粉体,利用TEM、XRD、BET、H2-TPR手段对样品进行了表征.实验结果表明,均相沉淀法所制得α-Fe2O3粉体晶粒尺寸为20nm左右,比表面积大,反应性能好;直接沉淀法所制得粉体晶粒尺寸为80nm左右,比表面积小,反应性能相对差.     

超微细Y2O3—ZrO2复合粉的制备及其活性研究

本文介绍以试剂级ZrOCl_2·8H_2O与Y_2O_3为原料,以H_2O_2为分散剂,制备杂质含量少、外形为球形,一次粒子径为75～550的超微细Y_2O_3—ZrO_2固溶体复合粉末的方法。     

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.     

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.     

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。