Ce0.67Zr0.33O2对CH4燃烧催化剂Fe2O3/Al2O3的改性作用

固定n(Ce)/n(Zr)比为0.67/0.33,用共沉淀法制得一系列CeO2-ZrO2-Al2O3固溶体.采用这些固溶体作载体,以Fe2O3为活性组分,用浸渍法制备了一系列催化剂.BET结果显示,将适量Ce0.67Zr0.33O2引入到Al2O3载体中有助于催化剂保持较高的比表面积.TPR结果显示,载体中引入适量的Ce0.67Zr0.33O2可以改善催化剂的氧化还原性能.XRD结果表明,Fe2O3在CeO2-ZrO2-Al2O3载体上呈现出良好的分散状况,老化前后催化剂的晶相结构基本无明显变化.特别是当载体中m(Ce0.67Zr0.33O2)∶m(Al2O3)的值为1∶2时,Fe2O3/CeO2-ZrO2-Al2O3催化剂在甲烷催化燃烧中显示出最佳的催化性能和抗高温老化性能.     

Syntheses, crystal structures and magnetic properties of a new nitronyl nitroxide NIT2-bithph and its manganese(II) compound [Mn(hfac)2(IMHBithph)]2·(NIT2-bithph)(C6H14)

A new nitronyl nitroxide NIT2-bithph (1) and its manganese(II) compound [Mn(hfac)₂(IMHBithph)]₂·(NIT2-bithph)(C₆H₁₄) (2) (hfac = hexafluoroacetylacetonate; NIT2-bithph = 4,4,5,5-tetramethyl-2-(bithiophenal-2-yl)imidazoline-1-oxyl-3-oxide; IMHBithph = 1-hydroxy-2-bithiophenal-4,4,5,5-tetramethyl-4,5-dihydro- 1H-imidazole) have been synthesized and structurally characterized by X-ray diffraction methods. The units of compound 1 were connected as one-dimensional chain by the intermolecular hydrogen bonds which afford an intermolecular antiferromagnetic interaction between nitronyl nitroxide radicals within the chain (J = −1.89 cm⁻¹). Compound 2 resulting from the reaction of Mn(hfac)₂·2H₂O and NIT2-bithph is dinuclear and includes the reduced amidino-oxide form of NIT2-bithph, it is made up of three parts: a [Mn(hfac)₂(IMHBithph)]₂ dimer unit, an uncoordinated NIT2-bithph radical and a noncoordinated solvent molecule of hexane, the molecule of radical is hydrogen bonded to its reduced form. Two reduced IMHBithph ligands bridge the two manganese(II) ions through their amidino-oxide oxygen atoms resulting in a small intramolecular antiferromagnetic interaction between the manganese ions (J = −1.55 cm⁻¹).     

测定啤酒和白葡萄酒中有机酸的离子排斥色谱法

研究了离子排斥色谱法分离测定啤酒和白葡萄酒中有机酸；选用常见的盐酸溶液作淋洗液，以四丁基氢氧化铵为再生液，考察了淋洗液浓度、流量等因素对分离和测定的影响，对啤酒和白葡萄酒中常见有机酸在阴离子排斥色谱柱上的保留行为进行了系统的研究；通过试验确定最佳的色谱条件为盐酸浓度1．10mmol/L，流量0．80mL/min；四丁基氢氧化铵浓度5.0mmol/L，流量1.10mL/min；并在该条件下，测定了啤酒和白葡萄酒中的有机酸。     

使用二元环糊精体系毛细管电泳法分离手性药物

采用高效毛细管区带电泳法，分别以羟丙基-β-环糊精（HP-β-CD）和高磺化-β-环糊精（HS-β-CD）及二者混合物为手性选择剂，研究了5种药物的对映体分离，并取得很好的对映体分离结果。比较了HP-β-CD和HS-β-CD手性识别能力，分析了二元环糊精体系的“协同效应”。     

BaCe1—xRExO3—0.5x的溶胶—凝胶法合成及离子导电性

用溶胶－凝胶法合成了系列钙钛矿结构的ＢａＣｅ１－ｘＲＥｘＯ３－０．５ｘ（ＲＥ＝Ｌａ，Ｎｄ，Ｓｍ，Ｅｕ，Ｇｄ，Ｄｙ，Ｈｏ，Ｅｒ和Ｙ）复合氧化物，通过ＸＲＤ和热分析对样品结构及生成过程进行了研究．测定了不同温度下样品的交流阻抗谱，讨论了稀土离子掺杂对ＢａＣｅＯ３电性质的影响．溶胶－凝胶法比固相反应法合成温度降低了６００～８００℃，稀土掺杂使ＢａＣｅＯ３离子导电率提高了１０～４０倍．     

测定饲料中喹乙醇含量的反相高效液相色谱法

建立了高效液相色谱法测定饲料中喹乙醇含量的方法 ;饲料用甲醇 -水提取 ,在380nm波长下检测 ,色谱柱为NOVA_PakC18(3.9mm×150mm ,4μm) ,流动相为甲醇 -水 (体积比为10∶90) ,流速为1.0mL/min ,喹乙醇质量浓度在2.5～20.0mg/L范围内与峰面积呈良好线性关系 ,相对标准偏差为1.2 %～1.6 % ,回收率为97 %～101%。     

网胰藻Hydroclathrus clathratus的化学成分研究

报道从中国南海网胰藻Hydroclathrus clathratus中分离得到3个单体化合物,经过MS,IR,1HNMR,13CNMR(DEPT),HMQC和HMBC等波谱技术鉴定为:(6R,7aS)-6-羟基-4,4,7a-三甲基-2,4,5,6,7,7a-六氢苯并呋喃-2-酮(1),1-(2-脱氧-β-D-呋喃核糖)-5-甲基-1,2,3,4-四氢嘧啶-2,4-二酮(2),尿嘧啶(3),并通过X射线单晶衍射实验确定化合物1的立体结构,其中化合物1是首次从自然界中分离得到.     

Single cell manipulation, analytics, and label-free protein detection in microfluidic devices for systems nanobiology

Single cell analytics for proteomic analysis is considered a key method in the framework of systems nanobiology which allows a novel proteomics without being subjected to ensemble-averaging, cell-cycle, or cell-population effects. We are currently developing a single cell analytical method for protein fingerprinting combining a structured microfluidic device with latest optical laser technology for single cell manipulation (trapping and steering), free-solution electrophoretical protein separation, and (label-free) protein detection. In this paper we report on first results of this novel analytical device focusing on three main issues. First, single biological cells were trapped, injected, steered, and deposited by means of optical tweezers in a poly(dimethylsiloxane) microfluidic device and consecutively lysed with SDS at a predefined position. Second, separation and detection of fluorescent dyes, amino acids, and proteins were achieved with LIF detection in the visible (VIS) (488 nm) as well as in the deep UV (266 nm) spectral range for label-free, native protein detection. Minute concentrations of 100 fM injected fluorescein could be detected in the VIS and a first protein separation and label-free detection could be achieved in the UV spectral range. Third, first analytical experiments with single Sf9 insect cells (Spodoptera frugiperda) in a tailored microfluidic device exhibiting distinct electropherograms of a green fluorescent protein-construct proved the validity of the concept. Thus, the presented microfluidic concept allows novel and fascinating single cell experiments for systems nanobiology in the future.     

Chiral conflict. The effect of temperature on the helical sense of a polymer controlled by the competition between structurally different enantiomers: from dilute solution to the lyotropic liquid crystal state

Helical polymers appended with paired structurally different enantiomers, which have opposing helical sense preferences, yield a new kind of relationship between optical activity and temperature, and also reveal unusual details of the nature of chiral interactions. Consistent with a statistical physical theory developed for these experiments, the proportion of the competing chiral groups, determined by synthesis, fixes the compensation temperature at which the helical senses are equally populated. The lyotropic liquid crystal state formed by these polymers yields therefore a nematic state at any chosen temperature over a very wide range, with a cholesteric state arising with tightening pitch as temperature deviates from this point. Far from the nematic temperature, the pitch reaches the nanometer scale and therefore the reflection of visible light. Before crossing zero at the nematic temperature, the optical activity becomes so large that it may be observed with the unaided eye through crossed polarizers.     

Fe3O4-LiMo3Se3 nanoparticle clusters as superparamagnetic nanocompasses

A scaleable chemical approach to functional nanoscale analogues of the magnetic compasses in magnetotactic bacteria is described. LiMo(3)Se(3)-Fe(3)O(4) nanowire-nanoparticle composites were synthesized by a reaction of 3-iodopropionic acid treated LiMo(3)Se(3) nanowire bundles with oleic acid-stabilized Fe(3)O(4) nanoparticles of 2.8, 5.3, and 12.5 nm size in tetrahydrofuran. Transmission electron micrographs show that the composite consists of Fe(3)O(4) nanoparticles attached to the surfaces of the 4-6 nm thick nanowire bundles. UV/vis spectra reveal absorptions from the nanowire (506 nm) and magnetite components (280-450 nm), and IR spectra show characteristic bands for the propionic acid linkers and for the residual oleic acid ligands on the magnetite particles. In the presence of excess oleic acid, the nanocomposites undergo rapid disassembly, suggesting that Fe(3)O(4) nanoparticles are bonded to nanowires via carboxylate groups from the linkers. Ultrasonication of a dispersion of the composite in THF produces individual LiMo(3)Se(3)-Fe(3)O(4) clusters, which are 340 +/- 107 nm long and 20 +/- 5 nm thick, depending on the sonication time and Fe(3)O(4) nanoparticle size. Field cooled and zero-field cooled magnetization measurements reveal that the blocking temperature (T(B) = 100 K) of the clusters with 5.3 nm Fe(3)O(4) is increased as compared to the free nanoparticles (T(B) = 30 K). Directional dipolar interactions in the clusters lead to magnetic anisotropy, which makes it possible to align the clusters in a magnetic field (900 Oe).