熔盐电解制备Ga—Nd合金的研究

Ga-Nd合金对磁性材料及半导体材料的研制是非常有用的。本文详细地研究了采用低熔点的镓作为阴极,从KCl-NdCl_3熔盐中电解制备廉价Ga-Nd合金的工艺条件。 本研究采用KCl-NdCl_3熔盐体系进行电解。KCl为分析纯。NdCl_3由Nd_2O_3(>99.99％)加过量NH_4Cl混合后,在大瓷蒸发皿中于350℃进行搅拌反应,直至产物完全溶于水。用滴定法确定原料中NdCl_3的含量。以金属镓作阴极(纯度为99.99wt％),阴     

LiF-KCl-KBr系和KF-NaCl-NaBr系熔盐相图研究

用目测变温法和X-射线相分析研究了LiF-KCl-KBr系和KF-NaCl-NaBr系熔盐相图.并在此基础上估算了熔盐溶液的正、负偏差情况,结合熔盐溶液的MonteCarlo法研究结果进行了讨论.     

低温合成超导体Ba1-xKxBiO3

先以BaCO3和Bi2O3为原料由传统的固相反应制备纯BaBiO3,然后在低温下将用KOH-KF熔盐处理这样的拓扑反应合成了Ba1-xKxBiO3超导体.所有样品均进行了粉末X射线衍射(XRD)和磁性表征.XRD结果表明,所得Ba1-xKxBiO3样品均为纯相,且均可用赝立方晶胞指标化.磁性测量表明所有样品具有超导电性,最高超导转变温度(Tc)为30.6 K.讨论了反应时间、前驱体与熔盐质量比对超导转变温度的影响.最佳的反应条件为:反应温度450°C,反应时间4 h,BaBiO3:KOH:KF质量比1:5:2.5.     

低温合成超导体Ba1-xKxBiO3

先以BaCO3和Bi2O3为原料由传统的固相反应制备纯BaBiO3,然后在低温下将用KOH-KF熔盐处理这样的拓扑反应合成了Ba1-xKxBiO3超导体.所有样品均进行了粉末X射线衍射(XRD)和磁性表征.XRD结果表明,所得Ba1-xKxBiO3样品均为纯相,且均可用赝立方晶胞指标化.磁性测量表明所有样品具有超导电性,最高超导转变温度(Tc)为30.6 K.讨论了反应时间、前驱体与熔盐质量比对超导转变温度的影响.最佳的反应条件为:反应温度450℃,反应时间4h,BaBiO3∶KOH∶KF质量比1∶5∶2.5.     

熔盐电解法制备硅纳米线的过程机理

采用FESEM、XRD和EDS分析了纳米二氧化硅烧结片在900℃的CaCl2熔盐中浸泡后结构和组成的变化,结果表明,由于纳米尺寸效应和CaCl2熔盐对二氧化硅的熔融(软化)具有助熔作用,纳米二氧化硅烧结片在900℃的CaCl2熔盐中由固态转变为熔融或半熔融态。根据对900℃的CaCl2熔盐中-1.2V恒电位电解不同时间电极片上反应区的结构和组成分析结果,提出了纳米二氧化硅电极片的硅/熔融二氧化硅/熔盐三相界面沿极片径向方向均匀推进的电解还原过程。通过对900℃的CaCl2熔盐中-1.2V恒电位电解5和15min电解产物的形貌、结构和成份分析,提出了硅纳米线在熔盐中的电化学成核与生长机理。     

共沉淀-熔盐焙烧法制备Y2O3:Eu及其发光性能的研究

采用共沉淀-熔盐焙烧法制备了Y2O3：Eu红色荧光粉,研究分析了EDTA、柠檬酸＋氨水、淀粉等3类络合剂、沉淀温度及熔盐对其发光性能、粒度及形貌等的影响.研究结果表明： 采用柠檬酸＋氨水为络合剂、草酸为沉淀剂制备钇铕的草酸盐前驱体,然后加入（Na2CO3＋S＋NaCl）复合熔盐在1200 ℃下焙烧2 h即可制得发光强度高出商用粉5%的近球形Y2O3：Eu.     

熔盐电解LiCl-KCl-AlCl3-La2O3共析出制备Al-Li-La合金

研究了LiCl-KCl-AlCl3-La2O3熔盐体系中共析出制备Al-Li-La合金的可行性。研究表明,在LiCl-KCl熔盐中,AlCl3将La2O3氯化为LaCl3,使电解制备Al-Li-La合金顺利进行。借助循环伏安法对熔盐体系的电化学行为进行分析发现,对质量比为45∶45∶5∶2的LiCl-KCl-AlCl3-La2O3熔盐,当阴极电流密度大于0.25 A/cm2,可以实现Al、Li和La的共析出。通过研究电解温度、阴极电流密度和电解时间对合金组成的影响,得到了较佳的电解参数:电解温度650℃,在LiCl-KCl混合熔盐中加入质量分数为5%的AlCl3和2%的La2O3,阴极电流密度12.5 A/cm2,电解时间1 h。X射线衍射对合金分析测试表明,合金主要由Al2La和βLi组成。     

NaCl-CsCl熔盐中Ce(Ⅲ)离子的阴极过程研究

以钨微盘为研究电极采用循环伏安法和方波伏安法研究了温度为873K的NaCl-CsCl熔盐中Ce3 离子的阴极行为.结果表明,摩尔比为1:2的NaCl-CsCl熔盐体系中Ce3 离子分两步还原,其电化学反应历程为:Ce3 e=Ce2 ,Ce2 2e-=Ce.进一步计算得到熔盐体系中Ce3 离子的扩散系数(D).     

制备方法对LaFeO3纳米粉体的影响

分别采用熔盐法和溶液燃烧法合成了钙钛矿型LaFeO3纳米粉体,系统研究了两种制备方法对粉体相结构、形貌的影响,用XRD、SEM和TG/DSC对纳米粉体进行了表征.结果表明:熔盐体系、煅烧温度、燃料类型和燃料/氧化剂的摩尔比对合成LaFeO3有重要的影响.450-750℃的熔盐NaNO2体系及650-800℃的熔盐NaN...     

LiCl-KCl熔盐中纯氧氧化提纯单壁碳纳米管

以LiCl-KCl(wLiCl∶wKCl=55∶45)熔盐为反应介质,对在熔盐中纯氧氧化提纯单壁碳纳米管(SWCNT)进行了研究.发现可以通过控制熔盐温度和氧气流量来控制氧化反应温和地进行.将5gSWCNT粗产品分散在200g熔盐中,在470℃下用300mL?min-1氧气氧化2h可获得3.8%SWCNT收率.采用TEM,SEM,TGA和Raman谱对提纯前后SWCNT的形貌和组成进行了分析,发现提纯后SWCNT产品中无定形碳被有效去除,而SWCNT结构未发现明显变化.     

A confirmatory method for the simultaneous extraction,separation, identification and quantification of Tetracycline,Sulphonamide, Trimethoprim and Dapsone residues in muscle by ultra-high-performance liquid chromatography–tandem mass spectrometry according to Commission Decision 2002/657/EC

A rapid confirmatory multi-residue method for the analysis of tetracyclines, sulphonamides, trimethoprim and dapsone by UPLC-MS/MS is described. The method is able to quantify and confirm the following 19 compounds, oxytetracycline, tetracycline, chlortetracycline, doxycycline, sulfadiazine, sulfathiazole, sulfapyridine, trimethoprim, sulfamerazine, sulfamethizole, sulfamethazine, sulfamethoxypyridazine, sulfamonomethoxine, sulfachlorpyridazine, dapsone, sulfamethoxazole, sulfisoxazole, sulfaquinoxaline and sulfadimethoxine. Samples are extracted with 0.1 M EDTA and acetonitrile, which is then evaporated under a stream of nitrogen and reconstituted in water. Following centrifugation and filtering, an aliquot is analysed by UPLC-MS/MS using positive electrospray ionisation and multiple reaction monitoring. The method is deemed rapid as all analytes are extracted by a single extraction technique, with no solid-phase extraction clean up required. Validation is according to Commission Decision 2002/657/EC and was carried out for bovine, porcine, ovine and poultry species. Specificity, recovery, repeatability, reproducibility, CCα and CCβ data is presented.     

Simultaneous analysis of pesticides from different chemical classes by using a derivatisation step and gas chromatography-mass spectrometry

This work presents a new method to analyse simultaneously by GC–MS 31 pesticides from different chemical classes (2,4 D, 2,4 MCPA, alphacypermethrin, bifenthrin, bromoxynil, buprofezin, carbaryl, carbofuran, clopyralid, cyprodinil, deltamethrin dicamba, dichlobenil, dichlorprop, diflufenican, diuron, fenoxaprop, flazasulfuron, fluroxypyr, ioxynil, isoxaben, mecoprop-P, myclobutanil, oryzalin, oxadiazon, picloram, tau-fluvalinate tebuconazole, triclopyr, trifluralin and trinexapac-p-ethyl). This GC–MS method will be applied to the analysis of passive samplers (Tenax^® tubes and SPME fiber) used for the evaluation of the indoor and outdoor atmospheric contamination by non-agricultural pesticides. The method involves a derivatisation step for thermo-labile or polar pesticides. Different agents were tested and MtBSTFA (N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide), a sylilation agent producing very specific fragments [M−57], was retained. However, diuron could not be derivatised and the isocyanate product was used for identification and quantification. Pesticides which did not need a derivatisation step were not affected by the presence of the derivatisation agent and they could easily be analysed in mixture with derivatised pesticides. The method can be coupled to a thermal-desorption unit or to SPME extraction for a multiresidue analysis of various pesticides in atmospheric samples.     

MORPHOLOGY EVOLUTION IN PTFE AS A FUNCTION OF MELT TIME AND TEMPERATURE Ⅱ. LOW MOLECULAR WEIGHT FOLDED CHAIN SINGLE CRYSTALS AND BAND STRUCTURES

The effect of sintering dispersed and bulk, low molecular weight (Mn = 50,000 Da), nano-emulsion polytetrafluoroethylene (PTFE) particles near their melting point is described. With the nascent particles consisting of ca.75 nm diameter, hexagonal, single crystals, sintering at, e.g., 350℃, results, initially, in merger of neighboring particles,followed by individual molecular motion on the substrate and the formation of folded chain, lamellar single crystals and spherulites, and on-edge ribbons. It is suggested these structures develop, with time, in the mesomorphic "melt". Sintering of the bulk resin yields extended chain, band structures, as well as folded chain lamellae; end-surface to end-surface merger,possibly by end-to-end polymerization, occurs with increasing time.     

Alkaloids of Nitraria schoberi. N-Methylnitrarine

Nitrarine, isonitrarine, schoberidine, isoschoberidine, nitramidine, nitraroxine, nitraraine, schoberine, dehydroschoberine, tetramethylenetetrahydro--carboline, dl-vasicinone, deoxypeganine, deoxyvasicinone, dihydronitraraine, nitraramine, nitraramine N-oxide, tetramethylenetetrahydro--carboline N-oxide, tryptamine, and a new alkaloid N-methylnitrarine were isolated from the aerial part ofNitraria schoberiL. Spectral data and chemical transformations were used to establish the structure of the last, which was found in nature for the first time.     

367名幼儿智力发育与血中五种元素相关性分析

为探讨血铜、锌、钙、镁、铁5种元素对儿童智力的影响及其相关性,采用首都儿科研究所编制的0—6岁儿童神经心理发育量表,对367名2—4岁儿童进行现场智力测试并对抚养人进行问卷调查;采集其指尖末梢血,运用原子吸收光谱仪检测了儿童血铜、锌、钙、镁、铁5种元素含量。结果表明,调查对象血铜、锌、钙、镁、铁5种元素低下,检出率分别为25．1％、76．6％、5．7％、1．4％、37．1％,城乡儿童全血铜、锌、钙存在明显差异（P〈0．05）;儿童智力低下检出率为2．4％,儿童智能发育与其年龄、母亲文化水平、是否接受学前教育、血锌、铁呈正相关,与血钙、铜呈负相关。提示该地区2—4岁儿童血铜、锌、铁低下检出率较高,智能发育总体较为合理,但受血铜、锌、铁等多种因素影响,提高父母文化素质,加强儿童早期教育及营养有助于促进儿童智能发育。     

Multi-Elemental Analysis as a Tool to Ascertain the Safety and the Origin of Beehive Products: Development,Validation, and Application of an ICP-MS Method on Four Unifloral Honeys Produced in Sardinia,Italy

Despite unifloral honeys from Sardinia, Italy, being appreciated worldwide for their peculiar organoleptic features, their elemental signature has only partly been investigated. Hence, the principal aim of this study was to measure the concentration of trace and toxic elements (i.e., Ag, As, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Te, Tl, V, and Zn) in four unifloral honeys produced in Sardinia. For this purpose, an original ICP-MS method was developed, fully validated, and applied on unifloral honeys from asphodel, eucalyptus, strawberry tree, and thistle. Particular attention was paid to the method’s development: factorial design was applied for the optimization of the acid microwave digestion, whereas the instrumental parameters were tuned to minimize the polyatomic interferences. Most of the analytes’ concentration ranged between the relevant LoDs and few mg kg⁻¹, while toxic elements were present in negligible amounts. The elemental signatures of asphodel and thistle honeys were measured for the first time, whereas those of eucalyptus and strawberry tree honeys suggested a geographical differentiation if compared with the literature. Chemometric analysis allowed for the botanical discrimination of honeys through their elemental signature, whereas linear discriminant analysis provided an accuracy level of 87.1%.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

电感耦合等离子体原子发射光谱测定混合稀土铜合金中稀土和非稀土元素

本文提出了用电感耦合等离子体原子发射光谱(ICP—AES)法直接测定混合稀土铜合金中13个非稀土和稀土元素。选用了合适的分析线对及ICP光源的工作参数。探讨了观察高度、功率、酸度、载气和基体量的变化对被测元素谱线强度的影响。不用化学分离,可一次同时测定La、Ce、pr、Nd、Sm、Sn、Zn、Fe、Al、Ni、Pb,Mg和Mn。测定范围(％):La_2O_3:0.096～6.4;CeO_2:0.24～16;Pr_6O_(11):0.0384～2.56;Nd_2O_3:0.096～6.4;Sn:0.096～3.2;Mg、Mn、Fe,Sm_2O_3:0.024～1.6;Zn:0.396～6.7;Pb:0.092～6.4;Ni:0.096～3.2;Al:0.0384～1.28。相对标准偏差±3.0～9.1％;回收率85～116％满足冶炼上的要求,得到了满意的结果。     

Unusual metals as electrode materials for electrochemical sensors

Although noble metals are still widely used in electroanalysis, a plethora of different nonconventional metals is now enriching the panorama of materials acting as the electrochemical transducer in sensing systems. In particular, Ti, Cu, Co, Fe, Mo, Ta, W, Rh, Bi, Sb, Te and Pb are discussed here in view of their peculiar physicochemical properties and of the interesting electrocatalytic activities ascribable to these elements and to the relevant metal oxide ultrathin films that spontaneously form at the electrode–solution interface. This behaviour, exploitable in electroanalysis for the detection of a number on analytes, is often accompanied by low price and high resistance to corrosion and to abrasion characterising these materials. These peculiarities encourage the possible use of the cited metals in a wide number of analytical frames, ranging from process control to bioimplantable sensing systems.     

Self-Assembling Drug Formulations with Tunable Permeability and Biodegradability

This review focuses on key topics in the field of drug delivery related to the design of nanocarriers answering the biomedicine criteria, including biocompatibility, biodegradability, low toxicity, and the ability to overcome biological barriers. For these reasons, much attention is paid to the amphiphile-based carriers composed of natural building blocks, lipids, and their structural analogues and synthetic surfactants that are capable of self-assembly with the formation of a variety of supramolecular aggregates. The latter are dynamic structures that can be used as nanocontainers for hydrophobic drugs to increase their solubility and bioavailability. In this section, biodegradable cationic surfactants bearing cleavable fragments are discussed, with ester- and carbamate-containing analogs, as well as amino acid derivatives received special attention. Drug delivery through the biological barriers is a challenging task, which is highlighted by the example of transdermal method of drug administration. In this paper, nonionic surfactants are primarily discussed, including their application for the fabrication of nanocarriers, their surfactant-skin interactions, the mechanisms of modulating their permeability, and the factors controlling drug encapsulation, release, and targeted delivery. Different types of nanocarriers are covered, including niosomes, transfersomes, invasomes and chitosomes, with their morphological specificity, beneficial characteristics and limitations discussed.